Stable Co-Catalyst-Free Photocatalytic H2 Evolution From Oxidized Titanium Nitride Nanopowders

TL;DR

This study demonstrates a stable, noble-metal-free photocatalyst derived from oxidized titanium nitride nanopowders that effectively produces hydrogen under sunlight, with potential for sustainable energy applications.

Contribution

It introduces a novel, simple thermal oxidation method to produce an active TiO2:Ti3+:N photocatalyst without noble metals, showing long-term stability and high activity.

Findings

Effective hydrogen evolution under sunlight conditions.

Stable performance over four months.

Requires small TiN particles for activation.

Abstract

In the present work, a simple strategy is used to thermally oxidize TiN nanopowder (ca. 20 nm) to an anatase phase of a TiO2:Ti3+:N compound. In contrast to the rutile phase of such a compound this photocatalyst provides photocatalytic activity for hydrogen evolution under AM1.5 conditions - this without the use of any noble metal co-catalyst. Moreover the photocatalyst is active and stable over extended periods of time (tested for 4 months). Importantly, to achieve successful conversion to the active anatase polymorph, sufficiently small starting particles of TiN are needed. The key factor for catalysis is the stabilization of the co-catalytically active Ti3+ species against oxidation by nitrogen present in the starting material.