Tailoring defects in SrTiO 3 by one step nanoarchitectonics for realizing photocatalytic nitrogen fixation in pure water.

Surface contamination of materials by nitrogenous impurities is a major problem that can bias the quantification of ammonia in photocatalytic N 2 fixation reactions. In this work, SrTiO 3 nanocubes were prepared by using a nitrogenous precursor and engineered with Ti 3+ sites and oxygen vacancy defects in a one-step solvothermal approach. It was observed that the synthesized materials were containing surface nitrogenous impurities and therefore a rigorous cleaning procedure was adopted to eliminate them to the best extent. The contribution of unavoidable surface impurities was deduced in the form of adventitious NH 3 by employing control experiments and a realistic photocatalytic NH 3 generation was achieved. It was found that pristine SrTiO 3 showed no photocatalytic activity, whereas one of the defected SrTiO 3 materials showed the highest NH 3 formation under natural sunlight in pure water, which was ascribed to the tuned defect sites, enhanced surface area and efficient separation of photogenerated charges. Based on the experimental results, a stringent protocol has been suggested for materials synthesis while working with nitrogenous precursors and for subsequent photocatalytic N 2 fixation experiments. Thus, the present study provides a simple and affordable procedure for catalyst synthesis for the studied application and expands the scope of perovskite oxide materials to fabricate efficient photocatalysts for sustainable NH 3 production.