Construction Of Copper Oxide Photocathode And It’s Application In Photoelectrocatalytic Reduction Of CO₂

Using CO₂ as a carbon source and driven by applied potential,CO₂ can be converted into green fuels by the assistance of solar energy,which is called photoelectrocatalytic reduction of CO₂,is an attractive and promising technological path in the global zero carbon emission campaign.The performance of photoelectrode is the core of rational design of photoelectrocatalytic reduction system,in which the light absorption,stability,catalytic activity and selectivity of photoelectrode are the key factors to be considered.Among all kinds of photocathode materials,copper-based materials are always the strong candidates because of their special selectivity for CO₂reduction products.Among the copper-based materials,copper-based oxides can be facile prepared and are rich in abundance,which have attracted much attention because of their special selectivity for reducing CO₂ to multi-carbon products.In this work,we mainly focus on improving the stability and light absorption properties of copper-based oxide photocathode.We get excellent photocathode by designing the structure of copper-based oxide electrode,the specific research contents are as follows:（1）The Cu₂O nanospheres（Cu₂O NS）were introduced into the surface of the electrodes prepared by thermal oxidation of Cu（TO-Cu_xO）or electrodeposition of Cu₂O（ED-Cu₂O）,to construct the Cu₂O NS/TO-Cu_xO and Cu₂O NS/ED-Cu₂O composite electrodes with stable activity.The Cu₂O nanospheres on the surface of the electrode were used as a protective layer to refrain from photocorrosion of the inner layer of active copper oxides.The stability of the electrode was effectively improved under the premise of ensuring the photocatalytic activity.The photoelectrocatalytic reduction of CO₂ by using these composite electrodes can respectively obtain 38.8%and 72.2%Faradaic efficiency of ethanol at their optimal potentials.（2）A photonic crystal light-enhanced double-layer copper oxide composite electrode was prepared by coupling the Si O₂/ETPTA photonic crystal film onto the back of the Cu₂O NS/ED-Cu₂O photocathode.By adjusting the photonic band gap,the thickness of double-layer copper oxide and the transmittance,we realized the enhancement of the photoelectric properties of the electrodes by photonic crystals.At the same time,the enhancement of photoelectrocatalytic activity by photonic crystals at a specific potential was preliminarily verified.