Local photothermal and photoelectric effect synergistically boost hollow CeO2/CoS2 heterostructure electrocatalytic oxygen evolution reaction

Abstract

Solar-assisted electrocatalytic oxygen evolution reaction (OER) plays a key role in energy conversion and storage technology. Herein, we provide the novel design and synthesis of an advanced category of CeO2/CoS2 heterostructures, which combines the local photothermal effect (LPTE) action of CeO2 and the photoelectric effect CoS2 to boost OER. Interestingly, the hollow framework, rich heterointerface, coupled local photothermal effect and photoelectric effect equip CeO2/CoS2 with remarkably excellent electrocatalytic OER performance. As a result, the optimized CeO2/CoS2-6 only needs an overpotential of 283 mV to reach 10 mA cm−2 as well as a smaller Tafel slop of 33.2 mV dec-1, outperforming the RuO2 catalyst (323 mA @ 10 mA cm−2). Upon combination of experimental data and mechanistic study, it is revealed that the enhanced OER performance is primarily ascribed to the photo-induced local thermal. partly resulting from photoelectric effect, where the photogenerated electron flow from CeO2 to CoS2 can photogenerated holes in CeO2 to boost water oxidation. This work is extremely expected to offer a novel avenue for the rational design and fabrication of outstanding OER electrocatalysts upon LPTE.