CoxP@NiCo-LDH heteronanosheet arrays as efficient bifunctional electrocatalysts for co-generation of value-added formate and hydrogen with less-energy consumption

The inefficiency of water splitting is mainly due to the sluggish anodic water oxidation reaction. Replacing water oxidation with thermodynamically more favorable selective methanol oxidation reaction and developing robust bifunctional electrocatalysts are of great significance. Herein, a hierarchical heteronanostructure with Ni–Co layered double hydroxide(LDH) ultrathin nanosheets coated on cobalt phosphide nanosheets arrays(CoxP@NiCo-LDH) are fabricated and used for co-electrolysis of methanol/water to co-produce value-added formate and hydrogen with saving energy. Benefiting from the fast charge transfer introduced by phosphide nanoarrays, the synergy in nanosheets catalysts with hetero-interface,CoxP@NiCo-LDH/Ni foam(NF) exhibits superior electrocatalytic performance(10 mA cm-2@ 1.24 V and-0.10 V for methanol selective oxidation and hydrogen evolution reaction, respectively). Furthermore,CoxP@NiCo-LDH/NF-based symmetric two-electrode electrolyzer drives a current density of 10 m A cm-2 with a low cell voltage of only 1.43 V and the Faradaic efficiency towards the generation of formate and H2 are close to 100% in the tested range of current density(from 40 to 200 m A cm-2). This work highlights the positive effect of hetero-interaction in the design of more efficient eletrocatalysts and might guide the way towards facile upgrading of alcohols and energy-saving electrolytic H2 co-generation.

2020 Roadmap on gas-involved photo-and electro-catalysis

Green reactions not only provide us chemical products without any pollution,but also offer us the viable technology to realize difficult tasks in normal conditions.Photo-,photoelectro-,and electrocatalytic reactions are indeed powerful tools to help us to embrace bright future.Especially,some gas-involved reactions are extremely useful to change our life environments from energy systems to liquid fuels and cost-effective products,such as H2 evolution(H2 production),02 evolution/reduction,CO2 reduction,N2 reduction(or N2 fixation) reactions.We can provide fuel cells clean H2 for electric vehicles from H2 evolution reaction(HER),at the same time,we also need highly efficient 02 reduction reaction(ORR) in fuel cells for improving the reaction kinetics.Moreover,we can get the clean oxidant O2 from water through O2 evolution reaction(OER),and carry out some reactions without posing any pollution to reaction systems.Furthermore,we can translate the greenhouse gas CO2 into useful liquid fuels through CO2 reduction reaction(CRR).Last but not the least,we can get ammonia from N2 reduction reaction(NRR),which can decrease energy input compared to the traditional Hubble process.These reactions,such as HER,ORR,OER,CRR and NRR could be realized through solar-,photoelectro-and electro-assisted ways.For them,the catalysts used play crucial roles in determining the efficiency and kinds of products,so we should consider the efficiency of catalysts.However,the cost,synthetic methods of catalysts should also be considered.Nowadays,significant progress has been achieved,however,many challenges still exist,reaction systems,catalysts underlying mechanisms,and so on.As extremely active fields,we should pay attention to them.Under the background,it has motivated us to contribute with a roadmap on ’GasInvolved Photo-and Electro-Catalysis’.