3D Burr-like Pt nanoparticles as co-catalyst decorated on TiO₂ nanotubes: an effective hydrogen production photoanode with enhanced photoelectrochemical performance

Noble metal Pt nanoparticles are typically decorated on photocatalyst as co-catalyst to reach reasonable photocatalytic performance. Hence, improving the photocatalytic efficiency with the use of minimum amount of Pt is very imperative and challenging due to the low abundance and high cost of Pt. In this study, a new strategy has been developed to fabricate 3D burr-like Pt nanoparticles co-catalyst on TiO₂ nanotube arrays via chemical alloying–dealloying method. It is noteworthy that in the first step, highly dispersed and uniform PtNi alloy particles were prepared by adding a certain amount of surfactant PVP and Triton X-100, and then the Pt nanoparticles with burr-like structure were obtained by the next acid dealloying treatment. Compared with reference samples loaded with pure bulk Pt nanoparticles (either big or small size) or bigger burr-like Pt nanoparticles, the obtained TiO₂ nanotubes loaded with ultra-fine burr-like Pt co-catalysts showed excellent photoelectrochemical water splitting for hydrogen production. The optimized sample showed more than 4 times enhancement in the H₂ production activity compared with reference sample which was loaded with pure bulk Pt particle. We ascribed this beneficial effect to the following factor: the ultra-dispersed Pt co-catalysts with burr-like structure provide a larger specific surface area and more branches as combinative sites with TiO₂ which form more effective Schottky junction to drive the separation of photogenerated holes and e⁻ and also inhibit their recombination. The present study provides a facile and effective route to design high-performance photoelectrode with burr-like Pt nanoparticles as co-catalysts for photoelectrochemical.