Scholars@Duke
Nico Hotz

Nico Hotz

Associate Professor of the Practice in the Thomas Lord Department of Mechanical Engineering and Materials Science
Thomas Lord Department of Mechanical Engineering and Materials Science
nico.hotz@duke.edu
303 Hudson Hall, Mems Department, Durham, NC 27708-0300
303 Hudson Hall, Mems Department, Durham, NC 27708

Selected Publications

Soliquidy: a descriptor for atomic geometrical confusion

Journal Article Npj Computational Materials · December 1, 2025 Tailoring material properties often requires understanding the solidification process. Herein, we introduce the geometric descriptor Soliquidy, which numerically captures the Euclidean transport cost between the translationally disordered versus ordered st ... Full text Cite

AFLOW4: Heading Toward Disorder

Journal Article High Entropy Alloys and Materials · March 1, 2025 AFLOW4 is the latest iteration of the AFLOW toolkit, specifically tailored to study high-entropy disordered materials. This upgrade includes innovative features like the Soliquidy module, based on the Euclidean transport cost between disordered and ordered ... Full text Cite

A priori procedure to establish spinodal decomposition in alloys

Journal Article Acta Materialia · March 1, 2024 Spinodal decomposition can improve a number of essential properties in materials, especially hardness. Yet, the theoretical prediction of the onset of this phenomenon (e.g., temperature) and its microstructure (e.g., wavelength) often requires input parame ... Full text Cite

Inducing Deep Sweeps and Vortex Ejections on Patterned Membrane Surfaces to Mitigate Surface Fouling.

Journal Article Membranes · January 2024 Patterned membrane surfaces offer a hydrodynamic approach to mitigating concentration polarization and subsequent surface fouling. However, when subjected to steady crossflow conditions, surface patterns promote particle accumulation in the recirculation z ... Full text Cite

A study of energy losses in the world's most fuel efficient vehicle

Conference 2019 IEEE Vehicle Power and Propulsion Conference Vppc 2019 Proceedings · October 1, 2019 The prototype fuel cell electric vehicle (FCEV) Maxwell currently holds the Guinness World Record for "Most Fuel-Efficient Vehicle" at 6,196 km/l (14,573 MPGe). The vehicle draws less than 21W of electrical power at 25 km/h. This work outlines the powertra ... Full text Cite

Towards an off-grid fecal sludge treatment unit: demonstrating energy positive thermal treatment.

Journal Article Gates open research · January 2019 Background: There is an unmet demand for community-scale fecal sludge treatment units (FSTUs) that serve communities of between 1,000 and 50,000 people and are able to operate in non-sewered and off-grid environments. An emerging industry standard f ... Full text Cite

Renewable hydrogen production by solar-powered methanol reforming

Journal Article International Journal of Hydrogen Energy · July 27, 2016 The present study demonstrates the possibility of generating hydrogen by methanol steam reforming at temperatures of 235–260 °C inside a non-concentrating solar collector, ideally for stationary fuel cell systems. In contrast to the current state-of-the-ar ... Full text Cite

Plasmon-assisted photothermal catalytic reactor for hydrogen generation

Journal Article Proceedings of the National Academy of Sciences of USA · 2015 Cite

Investigating operating conditions and mechanical performance of co-injected polylactic acid and polycaprolactone

Conference Annual Technical Conference ANTEC Conference Proceedings · January 1, 2015 To aid in advancing the functionality of bioplastics, co-injection moulding was investigated as a means to combine two biodegradable polymers: brittle, sugar-based polylactic acid (PLA) and tough polycaprolactone (PCL)..Procedural development reviewed the ... Cite

Hierarchical Nanostructures for Fuel Cells and Fuel Reforming

Chapter · November 11, 2014 This book provides systematic coverage of how nanostructured materials can be applied to energy devices, with an emphasis on the process of generation to storage and consumption. ... Cite

Novel non-concentrating solar collector for intermediate-temperature energy capture

Journal Article Solar Energy · January 1, 2014 Tremendous research efforts have been conducted studying the capturing and conversion of solar energy. Solar thermal power systems offer a compelling opportunity for renewable energy utilization with high efficiencies and excellent cost-effectiveness. The ... Full text Cite

Novel non-concentrated solar collector for solar-powered chemical reactions

Conference ASME 2013 7th Int Conf on Energy Sustainability Collocated with the ASME 2013 Heat Transfer Summer Conf and the ASME 2013 11th Int Conf on Fuel Cell Science Engineering and Technology Es 2013 · December 1, 2013 The purpose of this study is the proof that nonconcentrating solar-thermal collectors can supply the thermal energy needed to power endothermic chemical reactions such as steam reforming of alcoholic (bio-) fuels. Traditional steam reformers require the co ... Full text Cite

Flame-made CuO/ZnO/Al2O3 catalyst for methanol steam reforming

Conference ASME 2013 7th Int Conf on Energy Sustainability Collocated with the ASME 2013 Heat Transfer Summer Conf and the ASME 2013 11th Int Conf on Fuel Cell Science Engineering and Technology Es 2013 · December 1, 2013 In the present study, a catalyst produced by flame spray pyrolysis (FSP) was evaluated for its ability to produce hydrogen-rich gas mixtures. Catalyst particles fabricated by a novel flame spray pyrolysis method resulting in a highly active catalyst with h ... Full text Cite

Novel nano-scale Au/α-Fe2O3 catalyst for the preferential oxidation of CO in biofuel reformate gas

Conference ASME 2013 7th Int Conf on Energy Sustainability Collocated with the ASME 2013 Heat Transfer Summer Conf and the ASME 2013 11th Int Conf on Fuel Cell Science Engineering and Technology Es 2013 · December 1, 2013 Au/α-Fe2O3 catalyst was synthesized using a modified co-precipitation method to generate an inverse catalyst model. The effects of introducing CO2 and H2O during preferential oxidation (PROX) of CO were investiga ... Full text Cite

Novel nano-scale Au/α-Fe2O3 catalyst for the preferential oxidation of CO in biofuel reformate gas

Journal Article Journal of Catalysis · April 1, 2013 Au/α-Fe2O3 catalyst was synthesized using a modified co-precipitation method to generate an inverse catalyst model. The effects of introducing CO2 and H2O during preferential oxidation (PROX) of CO were investiga ... Full text Cite

Non-concentrated solar collector for solarthermal chemical reactions

Conference ASME International Mechanical Engineering Congress and Exposition Proceedings Imece · January 1, 2013 The purpose of this study is the proof that nonconcentrating solar-thermal collectors can supply the thermal energy needed to power endothermic chemical reactions such as steam reforming of alcoholic (bio-) fuels. Traditional steam reformers require the co ... Full text Cite

Flame-made catalyst for bio-methanol steam reforming

Conference ASME International Mechanical Engineering Congress and Exposition Proceedings Imece · January 1, 2013 In the present study, a catalyst produced by flame spray pyrolysis (FSP) was evaluated for its ability to produce hydrogen-rich gas mixtures. Catalyst particles fabricated by a novel flame spray pyrolysis method resulting in a highly active catalyst with h ... Full text Cite

Hybrid solar system for decentralized electric power generation and storage

Journal Article Journal of Solar Energy Engineering Transactions of the ASME · October 8, 2012 The present study investigates the feasibility, efficiency, and system design of a hybrid solar system generating electric power for stationary applications such as residential buildings. The system is fed by methanol and combines methanol steam reforming ... Full text Cite

3D micro-structures by piezoelectric inkjet printing of gold nanofluids

Journal Article Journal of Micromechanics and Microengineering · May 1, 2012 3D solid and pocketed micro-wires and micro-walls are needed for emerging applications that require fine-scale functional structures in three dimensions, including micro-heaters, micro-reactors and solar cells. To fulfill this demand, 3D micro-structures w ... Full text Cite

Hydrogen production from biofuel under sunlight: A hybrid approach

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · March 25, 2012 Link to item Cite

Digital selective growth of ZnO nanowire arrays from inkjet-printed nanoparticle seeds on a flexible substrate.

Journal Article Langmuir : the ACS journal of surfaces and colloids · March 2012 In this article, we introduce fully digital selective ZnO nanowire array growth on inkjet-printed seed patterning. Through proper natural convection suppression during hydrothermal growth, successful ZnO nanowire local growth can be achieved. Without any n ... Full text Cite

Nano-structured catalytic material for solar-powered biofuel reforming

Conference ASME International Mechanical Engineering Congress and Exposition Proceedings Imece · January 1, 2012 The main goal of this project is to combine two renewable energy conversion technologies (lowtemperature fuel cells and solarthermal collectors) to achieve synergies in terms of cost and energetic efficiency compared to systems based on a single energy sou ... Full text Cite

Micro- and nano-structured catalytic reactor for biofuel reforming in a solar collector

Conference ASME 2012 6th International Conference on Energy Sustainability Es 2012 Collocated with the ASME 2012 10th International Conference on Fuel Cell Science Engineering and Technology · January 1, 2012 In this study, a novel flow-based method is presented to place catalytic nanoparticles into a reactor by sol-gelation of a porous ceramic consisting of copper-based nanoparticles, silica sand, ceramic binder, and a gelation agent. This method allows for th ... Full text Cite

Next generation non-vacuum, maskless, low temperature nanoparticle ink laser digital direct metal patterning for a large area flexible electronics.

Journal Article PloS one · January 2012 Flexible electronics opened a new class of future electronics. The foldable, light and durable nature of flexible electronics allows vast flexibility in applications such as display, energy devices and mobile electronics. Even though conventional electroni ... Full text Cite

Solar-powered reformed methanol fuel cell system

Conference ASME 2012 10th International Conference on Fuel Cell Science Engineering and Technology Collocated with the ASME 2012 6th International Conference on Energy Sustainability Fuelcell 2012 · January 1, 2012 The present study investigates the feasibility, efficiency, and system design of a hybrid solar fuel cell system generating electric power for stationary applications such as residential buildings. The system is fed by methanol and combines methanol steam ... Full text Cite

Hydrogen production from biofuel under sunlight: A hybrid approach

Conference ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY · 2012 Cite

Hybrid solar system for stationary electric power generation

Conference 40th Ases National Solar Conference 2011 Solar 2011 · December 1, 2011 The present study investigates the feasibility, efficiency, and system design of a hybrid solar system generating electric power for stationary applications such as residential buildings. The system is fed by biomass-derived methanol and combines methanol ... Cite

Novel porous composite material containing catalytic nanoparticles for hydrogen production from biofuel

Conference Materials Research Society Symposium Proceedings · December 1, 2011 In this study, a novel flow-based method is presented to place catalytic nanoparticles into a reactor by sol-gelation of a porous ceramic consisting of copper-based nanoparticles, silica sand, ceramic binder, and a gelation agent. This method allows for th ... Full text Cite

Hybrid solar system for stationary electric power generation

Conference ASME 2011 5th International Conference on Energy Sustainability Es 2011 · December 1, 2011 The present study investigates the feasibility, efficiency, and system design of a hybrid solar system generating electric power for stationary applications such as residential buildings. The system is fed by methanol and combines methanol steam reforming ... Full text Cite

Hydrogen production on the rooftop from sunlight and biofuel

Journal Article SPIE Newsroom · November 2011 Full text Cite

A detailed surface reaction model for syngas production from butane over Rhodium catalyst

Journal Article International Journal of Hydrogen Energy · September 1, 2011 This paper presents numerical and experimental investigations of syngas production from butane. A surface reaction mechanism is used to model the reaction pathways. The butane reforming simulations and experiments are conducted in two reformers (tubular an ... Full text Cite

Porous media for catalytic renewable energy conversion

Conference Aip Conference Proceedings · January 1, 2011 A novel flow-based method is presented to place catalytic nanoparticles into a reactor by sol-gelation of a porous ceramic consisting of copper-based nanoparticles, silica sand, ceramic binder, and a gelation agent. This method allows for the placement of ... Full text Cite

Metal nanoparticle direct inkjet printing for low-temperature 3D micro metal structure fabrication

Journal Article Journal of Micromechanics and Microengineering · December 1, 2010 Inkjet printing of functional materials is a key technology toward ultra-low-cost, large-area electronics. We demonstrate low-temperature 3D micro metal structure fabrication by direct inkjet printing of metal nanoparticles (NPs) as a versatile, direct 3D ... Full text Cite

Exergetic analysis of solar-powered hybrid energy conversion and storage scenarios for stationary applications

Conference ASME 2010 4th International Conference on Energy Sustainability Es 2010 · December 1, 2010 The idea of this study is to investigate possibilities to use sunlight as the main energy source to generate and store electrical energy via different methods and technologies. Several systems consisting of photovoltaics, photoelectrolytic converters and s ... Full text Cite

Exergetic analysis of a solar-heated fuel cell system fed by methanol

Conference ASME 2010 4th International Conference on Energy Sustainability Es 2010 · December 1, 2010 The present study proposes a combination of solar-powered components (two heaters, an evaporator, and a steam-reformer) with a Proton Exchange Membrane fuel cell to form a powerplant that converts methanol to electricity. The solar radiation heats up the m ... Full text Cite

Large area flexible electronics fabrication by selective laser sintering of nanoparticles with a scanning mirror

Conference Materials Research Society Symposium Proceedings · October 15, 2010 The development of electric circuit fabrication on heat and chemically sensitive polymer substrates has attracted significant interest as a pathway to low-cost or large-area electronics. We demonstrated the large area, direct patterning of microelectronic ... Cite

A flexible direct methanol micro-fuel cell based on a metalized, photosensitive polymer film

Journal Article Journal of Power Sources · June 15, 2010 This paper presents and investigates a concept for a flexible direct methanol micro-fuel cell (FDMMFC) based on the microstructuring of a Cr/Au metalized, thin polymer film of photosensitive SU-8. The inscribed microchannels in the electrodes are 200 μm × ... Full text Cite

Nanoparticle selective laser sintering for large area flexible electronics fabrication with a scanning mirror

Conference 4th Pacific International Conference on Applications of Lasers and Optics, PICALO 2010 · June 11, 2010 The development of electric circuit fabrication on heat and chemically sensitive polymer substrates has attracted significant interest as a pathway to low-cost or large-area electronics. We demonstrated the large area, direct patterning of microelectronic ... Cite

Exergetic analysis and optimization of a solar-powered reformed methanol fuel cell micro-powerplant

Journal Article Journal of Power Sources · March 15, 2010 The present study proposes a combination of solar-powered components (two heaters, an evaporator, and a steam reformer) with a proton exchange membrane fuel cell to form a powerplant that converts methanol to electricity. The solar radiation heats up the m ... Full text Cite

Nanoparticle selective laser sintering for large area flexible electronics fabrication with a scanning mirror

Conference 4th Pacific International Conference on Applications of Lasers and Optics Picalo 2010 · January 1, 2010 The development of electric circuit fabrication on heat and chemically sensitive polymer substrates has attracted significant interest as a pathway to low-cost or large-area electronics. We demonstrated the large area, direct patterning of microelectronic ... Full text Cite

Hydrogen production with a solar steam-methanol reformer and colloid nanocatalyst

Journal Article International Journal of Hydrogen Energy · January 1, 2010 In the present study a small steam-methanol reformer with a colloid nanocatalyst is utilized to produce hydrogen. Radiation from a focused continuous green light laser (514 nm wavelength) is used to provide the energy for steam-methanol reforming. Nanocata ... Full text Cite

Simulation of the postcombustor for the treatment of toxic and flammable exhaust gases of a micro-solid oxide fuel cell

Journal Article Journal of Fuel Cell Science and Technology · November 1, 2009 This work investigates numerically a catalytic postcombustor for a micro-solid oxide fuel cell (SOFC) system. The postcombustor oxidizes toxic and explosive carbon monoxide (CO) and hydrogen exiting a solid oxide fuel cell to carbon dioxide and water. A si ... Full text Cite

On two-phase flow patterns and transition criteria in aqueous methanol and CO2 mixtures in adiabatic, rectangular microchannels

Journal Article International Journal of Multiphase Flow · August 1, 2009 This paper presents flow map investigations of adiabatic two-phase flow in square cross-sectioned, 200 μm deep microchannels fabricated in silicon, employing laser induced fluorescence microscopy. The influence of surface tension and nozzle geometry on the ... Full text Cite

Controlled free-form fabrication of nanowires by dielectrophoretic dispension of colloids

Journal Article Applied Physics Letters · July 31, 2009 The vertical growth of conductive gold nanowires in ambient atmosphere through on-demand dielectrophoretically guided deposition of nanoparticle-laden colloids is demonstrated. Accelerated by dielectrophoresis, rapidly evaporating colloidal droplets leave ... Full text Cite

Catalytic porous ceramic prepared in-situ by sol-gelation for butane-to-syngas processing in microreactors

Journal Article Aiche Journal · July 1, 2009 In this study, a novel flow-based method is presented to place catalytic nanoparticles into a reactor by sol-gelation of a porous ceramic consisting of Rh/ceria/zirconia nanoparticles, silica sand, ceramic binder, and a gelation agent. This method allows f ... Full text Cite

Large area flexible electronics fabrication by selective laser sintering of nanoparticles with a scanning mirror

Conference Icaleo 2009 28th International Congress on Applications of Lasers and Electro Optics Congress Proceedings · January 1, 2009 The development of electric circuit fabrication on heat and chemically sensitive polymer substrates has attracted significant interest as a pathway to low-cost or large-area electronics. We demonstrated the large area, direct patterning of microelectronic ... Full text Cite

Disk-shaped packed bed micro-reactor for butane-to-syngas processing

Journal Article Chemical Engineering Science · November 1, 2008 A novel disk-shaped packed bed micro-reactor containing Rh/ceria/zirconia nanoparticles is investigated with respect to catalytic butane-to-syngas processing at moderate temperatures of 550 °C. The main goal of this study is the development of an efficient ... Full text Cite

A micro-solid oxide fuel cell system as battery replacement

Journal Article Journal of Power Sources · February 15, 2008 The concept and the design of a micro-solid oxide fuel cell system is described and discussed. The system in this study is called the ONEBAT system and consists of the fuel cell PEN (positive electrode - electrolyte - negative electrode) element, a gas pro ... Full text Cite

Syngas production from butane using a flame-made Rh/Ce0.5Zr0.5O2 catalyst

Journal Article Applied Catalysis B: Environmental · 2007 Cite

Exergy analysis of a solid oxide fuel cell micropowerplant

Journal Article Journal of Power Sources · July 14, 2006 In this paper, an analytical model of a micro solid oxide fuel cell (SOFC) system fed by butane is introduced and analyzed in order to optimize its exergetic efficiency. The micro SOFC system is equipped with a partial oxidation (POX) reformer, a vaporizer ... Full text Cite

Exergetic analysis of fuel cell micropowerplants fed by methanol

Journal Article International Journal of Heat and Mass Transfer · July 1, 2006 In the present study, a hydrogen polymer electrolyte fuel cell (PEFC) micropowerplant in combination with a steam reformer fed by methanol and a direct methanol fuel cell (DMFC) micropowerplant are analyzed numerically regarding their exergetic efficiency. ... Full text Cite

Optimization of methane reforming in a microreactor-effects of catalyst loading and geometry

Journal Article Chemical Engineering Science · June 1, 2006 In this paper, the effect of the catalyst surface site density (catalyst amount) and reactor geometry on the reforming process of methane in a wall-coated, single-channel microreactor is investigated numerically. Such a reactor, consisting of a tubular flo ... Full text Cite