Superaerophobic Tremella-like Pt, B Codoped CoP Nanostructures as an Efficient and Durable Bifunctional Catalytic Electrode for Alkaline Water Splitting

Even though cobalt monophosphide (CoP) has been recognized as a prospective alternative to noble metal-based electrocatalysts in alkaline water splitting, further enhancement of the catalytic activity and durability of CoP in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) requires precise manipulation of its nanoscale spatial architecture and surface electronic structure. Herein, tremella-like Pt, B-codoped CoP nanostructures were successfully anchored on carbon cloth (Pt–B–CoP/CC) through a successive process involving wet chemical deposition, surface Pt impregnation, and phosphorization. The resultant Pt–B–CoP/CC exhibits excellent catalytic activity for both HER and OER, primarily attributed to (i) high-density active sites, (ii) enhanced surface conductivity, and (iii) appropriately modulated electronic structure via Pt, B codoping. In addition, Pt–B–CoP/CC exhibits superaerophobicity, enabling the maintenance of efficient exposure of active sites during electrolysis. In an alkaline medium (1.0 M KOH), the required overpotentials are 52.53 (at −10 mA cm–2) for HER and 224.37 mV (at 10 mA cm–2) for OER, which outperform most of the reported transition metal-based bifunctional catalytic electrode materials. The constructed Pt–B–CoP/CC||Pt–B–CoP/CC cell requires an ultralow cell voltage of 1.51 V (1.74 V) to drive a current density of 10 mA cm–2 (100 mA cm–2). After 100 h of continuous electrolysis, the cell voltage increment is almost negligible at 10 mA cm–2, while at 100 mA cm–2 it increases by only 1.97%, demonstrating the tremendous durability of Pt–B–CoP/CC and its potential applicability in industrial-grade electrolyzers. This study provides inspiration for designing and synthesizing advanced multifunctional catalytic electrodes with high efficiency and long-term stability.