Highly active and durable nitrogen-doped CoP/CeO₂ nanowire heterostructures for overall water splitting

Developing high-efficiency, low-cost, and durable bifunctional electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is greatly desirable and challenging. Herein, a highly active and durable nitrogen-doped CoP coupled CeO₂ nanowire heterostructure (N-CoP/CeO₂) electrocatalyst is prepared on carbon cloth. The resultant N-CoP/CeO₂ exhibits superb catalytic activities for OER and HER, featuring low overpotentials of 215 and 74 mV at 10 mA cm⁻² in 1.0 M KOH. The N-CoP/CeO₂ assembled water electrolyzer has super stability, which needs relatively low cell voltages of 1.52 V@10 mA cm⁻² over 42 days (≈95.9 % retention) and 1.80 V@400 mA cm⁻² over 21 days (≈94.4 % retention), outperforming most reported cost-effective electrocatalysts. Theoretical calculations reveal that the metallic heterostructure interfaces of N-CoP/CeO₂ possess a fast electron transfer pathway, optimized adsorption/desorption process of reactive intermediates, and reduced reaction energetic barriers, thus enhancing the electrocatalytic activity. Additionally, the robust three-dimensional configuration and the oxygen vacancies-rich CeO₂ component in N-CoP/CeO₂ are regarded as significant contributors to improving stability and promoting long-term durability.