A general synthetic strategy for N, P co-doped graphene supported metal-rich noble metal phosphides for hydrogen generation

Abstract

The exploitation of electrocatalysts with high activity and durability for HER is desirable for future energy systems, but it is still a challenge. NMPs have attracted increasing attentions, but the preparation process often needs toxic regents or dangerous reaction conditions. Herein, we develop a general green method to fabricate metal-rich NMPs anchored on NPG through pyrolyzing DNA cross-linked complexes. The obtained Ru2P-NPG exhibits an ultrasmall overpotential of 7 mV at 10 mA cm−2 and ultralow Tafel slope of 33 mV dec−1 in 1.0 mol L−1 KOH, even better than that of commercial Pt/C. In addition, Ru2P-NPG also shows low overpotentials of 29 and 78 mV in 0.5 mol L−1 H2SO4 and 1.0 mol L−1 PBS, respectively. The superior activity can be attributed to the ultrafine dispersion of Ru2P nanoparticles for more accessible sites, more defects formed for abundant active sites, the two-dimensional plane structure for accelerated electron transfer and mass transport, as well as the regulation of electron distribution of the catalyst. Moreover, the synthetic method can also be applied to prepare other metal-rich noble metal phosphides (Pd3P-NPG and Rh2P-NPG), which also exhibits high activity for HER. This work provides an effective strategy for designing NMP-based electrocatalysts.