Black TiO2–x Nanoparticles Decorated with Ni Nanoparticles and Trace Amounts of Pt Nanoparticles for Photocatalytic Hydrogen Generation
- Shubham BiswasShubham BiswasDepartment of Chemical Engineering, IIT(ISM) Dhanbad 826004, IndiaMore by Shubham Biswas,
- Ha-Young LeeHa-Young LeeDepartment of Energy Science and Engineering, DGIST, Daegu 42988, Republic of KoreaMore by Ha-Young Lee,
- Manohar PrasadManohar PrasadDepartment of Chemical Engineering, IIT(ISM) Dhanbad 826004, IndiaMore by Manohar Prasad,
- Abhishek SharmaAbhishek SharmaDepartment of Chemical Engineering, IIT(ISM) Dhanbad 826004, IndiaMore by Abhishek Sharma,
- Jong-Sung Yu ,
- Siddhartha SenguptaSiddhartha SenguptaDepartment of Chemical Engineering, IIT(ISM) Dhanbad 826004, IndiaMore by Siddhartha Sengupta,
- Devendra Deo Pathak , and
- Apurba Sinhamahapatra*
A cocatalyst plays an essential role in photoassisted hydrogen generation, and it is an almost inevitable component of a photocatalyst. Costly noble metal (e.g., Pt) cocatalysts exhibit almost irreplaceable efficiencies, and finding a suitable replacement is a challenging proposition. Controlled synthesis of a nanoparticle cocatalyst on semiconductors at the nanoscale level is one of the most promising approaches to accomplish the Pt equivalent activity. Herein, a photodeposited metallic Ni-based cocatalyst containing a small amount of Pt (<2 atom % with respect to Ni) on reduced/black TiO2–x is introduced. The developed cocatalyst (2.21 wt % Ni and 0.094 wt % Pt with respect to TiO2–x) exhibits better charge separation efficiency and photoassisted hydrogen generation rate than an only-Pt (0.91 wt %) cocatalyst from methanol–water. The rates are 69 and 3.1 mmol g–1 h–1 for a Ni-based cocatalyst, while 65 and 2.5 mmol g–1 h–1 for a Pt cocatalyst, respectively, under ultraviolet–visible and visible light. A small amount of Pt ensures the photodeposition of Ni nanoparticles adjacent to Pt nanoparticles, enhancing the charge migration from the reduced TiO2–x surface for hydrogen evolution. It is found that in the absence of Pt, the photodeposited Ni(OH)2 is obtained instead of metallic Ni nanoparticles, which exhibits a comparatively low hydrogen generation rate. The present study opens an alternative way to cocatalyst design and fabrication by the controlled synthesis of nanoparticles for a wide range of photocatalytic conversions facilitated by enhanced charge separation.
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