Scalable processing hollow tungsten carbide spherical superstructure as an enhanced electrocatalyst for hydrogen evolution reaction over a wide pH range

From atomic bonding to heterointerfaces: Co2P/WC constructed by lacunary polyoxometalates induced strategy as efficient hydrogen evolution electrocatalysts at all pH values

Herein, a novel in-situ "atomic binding to heterointerface" strategy is proposed to obtain Co₂P/WC@NC/CNTs catalyst with abundant heterointerface between cobalt phosphide and tungsten carbide (Co₂P/WC) by the polyoxometalates (POMs)-based metal-organic frameworks (MOFs) precursor. The natural quasi interfaces in K₁₀[Co₄(H₂O)₂(PW₉O₃₄)₂] molecule crucially guide the abundant Co₂P/WC heterointerfaces down to atomic level. Meanwhile, MOFs cages can effectively encapsulate nanosized POMs at molecular level to control the size and dispersion of Co₂P/WC nanoparticle, while carbon nanotubes (CNTs) enhance conductivity at nanoscale level. The interfacial electronic modulation between Co₂P and WC lowering the energy barrier of the rate determining step, thus Co₂P/WC@NC/CNTs showed reasonable hydrogen evolution reaction (HER) activity and stability in all-pH media including sea water. This work provides a "bottom-up" synthetic strategy for confined heterostructures, thus offering the prospect for more efficient interfacial charge modulation.

Structure-controlled tungsten carbide nanoplates for enhanced hydrogen evolution reaction

Developing a low-cost and durable non-noble metal eletrocatalyst for hydrogen evolution reaction (HER) is critical in efficient hydrogen production. Herein, tungsten carbide nanoplates (WC NPs) with typical mesoporous structure were prepared by a controlled hydrothermal reaction followed by a gas-solid carburization process. The crystal phases, microstructure and chemical components of the nanoplates were characterized, and their electrochemical properties were measured. The results show that the as-prepared WC NPs expose active sites upmost, and exhibit enhanced conductivity and superior HER performance in acid solution in terms of a small η 10 (overpotential to obtain a current density of 10 mA cm−2) of 120 mV, a Tafel slope of 58 mV dec−1 and outstanding long-term cycling stability. These indicate that the HER properties of WC NPs are dramatically enhanced compared to that of all phase pure WC materials reported in recent years. This enhancement can be attributed to their unique structural and electronic properties, which can be exploited to improve the electrochemical properties of traditional non-noble metal material.