Ca2+ doped TiO2 nano-sized polygon plates with oxygen vacancies for photocatalytic hydrogen evolution

Abstract

Photocatalytic hydrogen evolution using suitable photocatalysts in water is a sustainable way of energy production. In this paper, Ca2+ doped TiO2 nano-sized polygon plates with oxygen vacancies were synthesized. The incorporation of Ca2+ induces the loss of oxygen and the formation of oxygen vacancies in the TiO2 lattice, confirmed by XPS and EPR. TiO2 with 0.040% Ca adding amount shows the best photocatalytic hydrogen production activity (4485 μmol g−1 h−1) with the apparent quantum efficiency of 46.4% at 370 nm, higher than undoped TiO2 (2182 μmol g−1 h−1). The successful incorporation of Ca2+ and the formation of oxygen vacancies effectively inhibit the recombination of carriers in the reaction process and enhance the photocatalytic hydrogen production activity.