Hydrogen production via microwave-induced water splitting at low temperature

Abstract

Supplying global energy demand with CO2-free technologies is becoming feasible thanks to the rising affordability of renewable resources. Hydrogen is a promising vector in the decarbonization of energy systems, but more efficient and scalable synthesis is required to enable its widespread deployment. Here we report contactless H2 production via water electrolysis mediated by the microwavetriggered redox activation of solid-state ionic materials at low temperatures (<250 ºC). Water was reduced via reaction with non-equilibrium gadolinium-doped CeO2 that was previously in situ electrochemically deoxygenated by the sole application of microwaves. The microwave-driven reduction was identified by an instantaneous electrical conductivity rise and O2 release. This process was cyclable, whereas H2 yield and energy efficiency were material-and power-dependent. Deoxygenation of low-energy molecules (H2O or CO2) led to the formation of energy carriers and enabled CH4 production when integrated with a Sabatier reactor. This method could be extended to other reactions such as intensified hydrocarbons synthesis or oxidation.Sustainability of industry, transportation and energy management will rely on CO2-free technologies and renewable electricity, which are boosted by the rising affordability of photovoltaic solar and wind turbine parks. The electrification of industry and transport will strongly contribute to limiting greenhouse gas emissions 1,2 by using CO2-neutral energy carriers or chemical raw materials; however, the intermittent nature of renewables

Catalytic effect of laser-combined atmospheric pressure plasma in lowering the reduction temperature of hematite

“…A few studies on thermochemical redox reactions via microwave heating have been reported. 12,28,29 The studies showed that the direct radiation of microwave can promote the loss of lattice oxygen on metal oxides. The microwave-driven plasma introduced in the current work, however, is positioned far from the surface.…”

“…In addition, the absorption of plasmagenerated electrons is expected to facilitate the loss of lattice oxygen and the subsequent re-distribution of electron charge in metal oxides. 12,13 Those rich effects of plasma on both reactants and metal oxide catalysts could reduce the reduction temperature or enhance the reaction kinetics at a given temperature. 8,14 Second, plasma can induce a self-heating effect in the applied catalyst sample, which considerably diminishes the heating demand for the reactor.…”

Evaluation of Er Doped CeO2-δ as Oxygen Transport Membrane

“…Charge compensation occurs via oxygen vacancies, which represent the oxygen storage capacity. This redoxactivity is suitable for a wide range of applications, e.g., the electrolyte in solid oxide fuel cells (SOFC), oxygen permeating dense membranes, automotive exhaust control, soot oxidation in the automotive industry, catalyst for steam reforming, water-gas shift, hydrogen production, and oxidation reactions [1][2][3][4][5][6].…”

Selective catalytic oxidation of ammonia to nitric oxide via chemical looping

“…One method towards process intensification is chemical looping, whereby oxidation reactions are decoupled into twostep, spatially separated cyclic redox processes. [20][21][22][23] Chemica l looping is a new frontier for producing valuable chemicals in a clean and efficient manner, [24][25][26][27][28] and has been demonstrated for processing methane, [28][29][30][31][32][33][34][35] biofuels, 36,37 syngas, 38,39 coal and carbonaceous feedstocks 22,40,4 1 with low cost, reduced emissions and higher energy efficiency. Herein, we proposed and validat ed the first chemical looping ammonia oxidation (CLAO) process .…”