Energy-Confined Solar Thermal Ammonia Synthesis with K/Ru/TiO 2-x H x

Abstract Haber–Bosch thermal ammonia synthesis is of energy-intensive nature. Using solar energy for ammonia synthesis is idealized for both energy and environment problems, but remains great challenges. Generally, the diffuse solar flux and inefficient utilization cannot meet the energy demand for NH 3 production. Here we develop a solar thermal avenue, realizing highly efficient solar ammonia synthesis over K/Ru/TiO 2-x H x . The supported Ru is efficient for nitrogen activation because of the electron donation from TiO 2-x H x and free from H 2 poisoning, because the interfacial TiO 2-x H x accepts H atoms from Ru and then delivers them to the Ru activated N 2 to form Ti-NH x (x = 1–3) even at room temperature. When only irradiated with sunlight, this catalyst absorbs sunlight in the whole UV–vis-NIR region and reaches 360 °C by its plasmonic behavior, exhibiting a Haber–Bosch thermocatalysis-comparable NH 3 generation rate. This solar thermal approach with K/Ru/TiO 2-x H x provides a promising renewable way for ammonia synthesis.