Porous TiWO3/SrWO4 with high titanium molar ratio for efficient photoelectrocatalytic nitrogen reduction under mild conditions.

Ammonia synthesized by nitrogen reduction is the most promising new energy material. Photoelectrocatalytic (PEC) nitrogen reduction reaction (NRR) occurs under ambient conditions and is the optimal alternative to the energy-intensive Haber-Bosch method. Here, we report the one-step reaction synthesis of Ti–WO 3 /SrWO 4 as a photocathode for ammonia synthesis. First-principles calculations demonstrate that Ti doping can afford nitrogen-adsorption sites, and Ti3+ undergoes chemical adsorption and becomes a nitrogen-activation site by providing electrons to nitrogen. Under light irradiation, the photogenerated electrons are captured by Ti4+; this is conducive to the activation and regeneration of Ti3+, thus forming a nitrogen fixation cycle and improving the nitrogen fixation yield. At − 0.5 V vs. RHE, the ammonia synthesis efficiency reaches 11.17 μg h-1 cm-2, which is four times that of SrWO 4. Furthermore, the high stability and N-gas sensitivity of Ti–WO 3 /SrWO 4 in the NRR indicate that it can be used as an efficient and stable photoelectrocatalyst for ammonia synthesis. [Display omitted] • SrWO 4 firstly utilized as an effective photoelectrocatalyst for N 2 fixation. • Ti-WO 3 /SrWO 4 was synthesized by a one-step reaction based on H 2 WO 4. • N 2 is more easily adsorbed on Ti to facilitate the NRR reaction. • Ti-WO 3 /SrWO 4 PEC synthesis of ammonia is greatly improved. [ABSTRACT FROM AUTHOR]