N-doped TiO(2) nanotube arrays with uniformly embedded Co(x)P nanoparticles for high-efficiency hydrogen evolution reaction

Efficient and stable non-precious metal based electrocatalysts are crucial to the hydrogen evolution reaction (HER) in renewable energy conversion. Herein, Co(x)P nanoparticles (NPs) are uniformly embedded in N-doped TiO(2) nanotube arrays (Co(x)P/N-TiO(2) NTAs) by low-temperature phosphorization of the precursor of metallic cobalt NPs embedded in N-doped TiO(2) NTAs (Co/N-TiO(2) NTAs) which were fabricated by phase separation of CoTiO(3) NTAs in ammonia. Owing to the abundant exposed surface active sites of Co(x)P NPs, tight contact between the Co(x)P NPs and TiO(2) NTAs, fast electron transfer in N-doped TiO(2), and channels for effective diffusion of ions and H(2) bubbles in the tubular structure, the Co(x)P/N-TiO(2) NTAs have excellent electrocatalytic activity in HER exemplified by a low overpotential of 180 mV at 10 mA cm(−2) and small Tafel slope of 51 mV dec(−1) in 0.5 M H(2)SO(4). The catalyst also shows long-term cycling stability and is a promising non-precious metal catalyst for HER.