Boosting hydrogen adsorption via manipulating interfacial electronic structure of NiPx for enhanced alkaline seawater electrolysis

The development of transition metal phosphides (TMPs) electrocatalysts with appropriate binding strength towards intermediates and resistant to chlorine in alkaline seawater electrocatalysis remains a formidable challenge. Herein, an approach for manipulating electron redistribution in Ni 2 P/Ni 5 P 4 treated by Co cationic doping engineering (denoted as Act-Co-NiPx) is proposed, exhibiting excellent catalytic activities and stability toward HER in alkaline seawater solution. First-principles calculations demonstrate that the Co doping can effectively adjust the electron redistribution of Ni 2 P/Ni 5 P 4 , resulting in a reduction in the hydrogen adsorption free energy for HER and an acceleration in the interfacial charge transfer. Furthermore, the enhanced Cl - adsorption energy avoids the toxicity of Cl - to the active sites in alkaline seawater splitting. Consequently, the resulting Act-Co-NiPx catalyst demonstrates remarkable HER performance with low overpotentials of 77 and 97 mV at a current density of 10 mA cm −2 in both 1.0 M KOH and 1.0 M KOH+Seasalt electrolytes. Furthermore, the seasalt electrolyzer assembled from Act-Co-NiPx achieves the low cell voltage of 1.63 V at 10 mA cm −2 . This work demonstrates a feasible method for designing cost-effective and stable catalysts with excellent selectivity via regulating the electronic structure of TMPs for seawater electrolysis.