Phosphorus-modified tungsten nitride/reduced graphene oxide as a high-performance, non-noble-metal electrocatalyst for the hydrogen evolution reaction

Phosphorus-modified tungsten nitride/reduced graphene oxide (P-WN/rGO) is designed as a high-efficient, low-cost electrocatalyst for the hydrogen evolution reaction (HER). WN (ca. 3 nm in size) on rGO is first synthesized by using the H3[PO4(W3O9)4] cluster as a W source. Followed by phosphorization, the particle size increase slightly to about 4 nm with a P content of 2.52 at %. The interaction of P with rGO and WN results in an obvious increase of work function, being close to Pt metal. The P-WN/rGO exhibits low onset overpotential of 46 mV, Tafel slope of 54 mV dec(-1), and a large exchange current density of 0.35 mA cm(-2) in acid media. It requires overpotential of only 85 mV at current density of 10 mA cm(-2), while remaining good stability in accelerated durability testing. This work shows that the modification with a second anion is powerful way to design new catalysts for HER.