Interfacial electronic modulation of CoP-CoO p-p type heterojunction for enhancing oxygen evolution reaction

Heterojunction can effectively improve oxygen evolution reaction (OER) activity by regulating the interfacial electronic structure of catalysts. However, p-p type heterojunction OER catalysts have obtained less attention, and the corresponding catalytic mechanisms are unclear either. Herein, the self-supported CoP-CoO p-p type heterojunction arrays are fabricated on carbon cloth substrate (CoP-CoO/CC). Band structure analysis shows that the formation of p-p heterojunction can drive the electrons from CoO to flow into CoP. This electronic modulation contributes to positively charged regions on the CoO and enhances the OH- adsorption during OER, proven by X-ray photoelectron spectroscopy and methanol molecular detection, respectively. As a result, the CoP-CoO/CC electrode only needs 210 mV overpotential to drive a current density of 10 mA cm(-2) in an alkaline medium, superior to the most reported OER catalysts. Additionally, the CoP-CoO/CC also exhibits an ideal hydrogen evolution reaction response, and a water splitting system has been successfully constructed which can drive a 10 mA cm(-2) within 1.65 V. This study supplies insight for catalytic origins p-p type heterojunctions OER catalyst, which provides a reference value for the efficient and reasonable design of heterojunction catalysts. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

The study successfully improved the catalytic activity of oxygen evolution reaction by fabricating a CoP-CoO p-p type heterojunction array, providing insights for the design of efficient heterojunction catalysts.