Surface modification of photocatalytic materials to give better activity and potentially extending the response into the visible spectrum, is an area of active research. In this work, DFT modelling suggests that surface modification of rutile and anatase TiO₂ with partially oxidised copper clusters can induce a red shift in the photo-action spectrum. Copper clusters were synthesised and characterised separately before TiO₂ nanoparticle surface modification. Characterisation of copper clusters and photocatalysts modified with copper clusters showed that ex-situ synthesis can control the size of surface clusters. Sub-nanometre clusters of copper maintained their size and morphology upon attachment to the photocatalyst surface. The copper clusters were determined to be a mixture of Cu(0) and Cu(I), and no significant change in the oxidation state was observed following surface modification or following photoelectrochemical measurements. Experimental measurements including UV–Vis spectroscopy and valence band XPS showed a small red shift the band gap correlating to the DFT predictions. Photoelectrochemical characterisation showed an enhancement in the UV photocurrent response and a small red shift in the effective band gap for the surface modified TiO₂.

光催化材料的表面改性可以提供更好的活性，并可能将响应扩展到可见光谱，这是积极研究的领域。在这项工作中，DFT建模表明具有部分氧化的铜簇的金红石和锐钛矿型TiO _2的表面改性可引起光作用谱中的红移。在TiO ₂之前分别合成并表征了铜团簇纳米粒子表面改性。铜簇和铜簇修饰的光催化剂的表征表明，异位合成可以控制表面簇的大小。附着在光催化剂表面上的亚纳米级铜簇保持其尺寸和形态。确定铜簇为Cu（0）和Cu（I）的混合物，表面改性或光电化学测量后未观察到氧化态的显着变化。包括UV-Vis光谱学和价带XPS在内的实验测量结果表明，与DFT预测相关的能带隙出现了小的红移。光电化学表征表明，表面改性的TiO的紫外光电流响应增强，有效带隙小的红移₂。