Modification of Ni2P with LaPO4 for efficiently photocatalytic and electrocatalytic production of green-H2

Catalysts with excellent photocatalytic and electrocatalytic properties were highly desirable for improving hydrogen evolution reaction (HER) to produce green-H2. Herein, a series of La-Ni-P samples were prepared from one-pot hydrothermal system and investigated for HER. The samples were identified in (LaPO4)m/Ni2P nanocomposite structure with adjustable molar ratio m in 0.14–0.58 by ICP-OES, XRD, XPS and HRTEM characterization techniques. In dye (EY)-sensitized photocatalytic system, 9-fold enhancement in H2 evolution rate was achieved on (LaPO4)0.22/Ni2P in contrast to Ni2P (5450 versus 625 µmol h−1 g−1), and the obvious improvement in separation and transfer efficiency of photo-induced charge was demonstrated to be responsible for the superior HER performance on LaPO4/Ni2P interface. Electrocatalytic measurements disclosed that the overpotential for the reduction step to produce H2 involved in HER would reduce from 312 mV on Ni2P to 191 mV on (LaPO4)0.22/Ni2P with obviously lowered Tafel slope, the feature was supported by the observation that charge-transfer resistance (EIS analysis) on the sample (116 Ω) was much lower than that on Ni2P (331 Ω). These results clarified that LaPO4 could act as an attractive component to improve HER performance of Ni-phosphide-based catalysts, the favorable and compatible photocatalysis and electrocatalysis features manifested by LaPO4/Ni2P interface gifted phosphate/phosphide composites the potential as promising catalysts for clean production of H2.