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 M-centers 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. Nanostructured Co/Fe binary phosphides embedded in N, S, O ternary-doped carbon matrix by facile one-step low-temperature pyrolysis-phosphating approach from a N, S-rich bimetallic MOF to drive water splitting. By adjusting the phosphating temperature, the optimum CoFeP@NSOC-400 exhibits excellent bifunctional electrochemical performances for HER and OER in an alkaline electrolyte. When CoFeP–NSOC-400 is loaded on the foamed nickel for water splitting, a lower voltage 1.62 V is obtained to reach a current density of 10 mA cm−2. This paper proposes a one-step and low-cost phosphating method to obtain nanostructured bimetallic phosphides containing heteroatom doping carbon matrix, showing prominent electrocatalytic performance for water splitting. [Display omitted] • MOFs-derived Co/Fe TMPs embedded in N, S, O ternary-doped carbon matrix. • Co/Fe TMPs were fabricated by one-step low-temperature pyrolysis-phosphating approach. • The optimized TMP is a remarkable bifunctional electrocatalyst for efficient water splitting. [ABSTRACT FROM AUTHOR]