MOFs template derived Co/Fe binary phosphide nanocomposite embedded in ternary-doped carbon matrix for efficient water splitting

Transition metal phosphides (TMPs) are regarded as highly efficient electrocatalysts due to highly active surface sites, electrical conductivity, and chemical stability, which result from the high electrocatalytic activity of the Mcenters and P-sites. Thus, the aim of our work is to obtain highly efficient TMPs electrocatalysts by a facile and controllable strategy. We used N, S-rich Co/Fe bimetallic metal-organic framework as template to prepare ceramic Co/Fe binary phosphides embedded in N, S, O ternary-doped carbon matrix (CoFeP@NSOC). By means of a facile one-step low-temperature pyrolysis-phosphating approach, the optimized ceramic material CoFeP@NSOC-400 showed remarkable bifunctional electrocatalytic performances in an alkaline electrolyte, which only requires 176 and 240 mV overpotentials to achieve 10 mA cm-2 current density for HER and OER, respectively. Furthermore, when CoFeP@NSOC-400 is loaded on the highly conductive nickel foam (NF) for water splitting, it reaches a current density of 10 mA cm-2 at a low cell voltage of 1.62 V, superior to pure NF and other reported metal-phosphide electrocatalysts, at the same time, CoFeP@NSOC-400 shows negligible performance degradation and a relative current loss of only 4.3% for 40000 s continuous operations. These results indicate CoFeP@NSOC derived by MOFs through pyrolysis-phosphating is an ideal electrocatalysts for energy conversion applications.

Automated summary

In this study, transition metal phosphides (TMPs) were prepared as highly efficient electrocatalysts using a simple and controllable strategy. The optimized ceramic material CoFeP@NSOC-400 showed remarkable bifunctional electrocatalytic performances, with low overpotentials for HER and OER in an alkaline electrolyte. Furthermore, when loaded on a conductive nickel foam, CoFeP@NSOC-400 exhibited superior performance in water splitting with negligible degradation over extended operation. These results highlight the potential of CoFeP@NSOC derived by MOFs through pyrolysis-phosphating as ideal electrocatalysts for energy conversion applications.