Surface engineering-modulated porous N-doped rod-like molybdenum phosphide catalysts: towards high activity and stability for hydrogen evolution reaction over a wide pH range

Abstract

Electrochemical water splitting is an economic, green and sustainable route to produce hydrogen through the hydrogen evolution reaction (HER). Nowadays, noble metal-free phosphides have been widely used as catalysts in the HER, showing potential applications for both renewable energy production and environmental remediation. Nevertheless, developing surface self-doped MoP electrocatalysts with high HER performances in a wide pH range still remains a challenge. In this work, a novel synthesis strategy was developed to fabricate porous one-dimensional (1D) nitrogen-doped molybdenum phosphide (N-MoP) nanorods. The prepared N-MoP-800 catalyst exhibits a low onset potential of 65 mV and low Tafel slope of 58.66 mV dec⁻¹ in 0.5 M H₂SO₄, which is almost 2 times higher than that of the pristine MoP nanorod anode. Furthermore, the N-MoP materials show long-term durability for 12 h in a wide pH range. The synergistic effects of pyridinic N and N doping in MoP are responsible for the high catalytic activity of N-MoP under acidic conditions, while the N-Mo component plays a key role in enhancing the HER activity of N-MoP. These interesting findings are helpful for the rational design of highly active HER catalysts. More importantly, this study provides a new strategy to synthesize highly active catalysts with low costs for clean energy conversion.