Synergistic effects of carbon doping and coating of TiO₂ with exceptional photocurrent enhancement for high performance H₂ production from water splitting

The “one pot” simultaneous carbon coating and doping of TiO₂ materials by the hydrolysis of TiCl₄ in fructose is reported. The synergistic effect of carbon doping and coating of TiO₂ to significantly boost textural, optical and electronic properties and photocurrent of TiO₂ for high performance visible light H₂ production from water splitting has been comprehensively investigated. Carbon doping can significantly increase the thermal stability, thus inhibiting the phase transformation of the Titania material from anatase to rutile while carbon coating can suppress the grain aggregation of TiO₂. The synergy of carbon doping and coating can not only ensure an enhanced narrowing effect of the electronic band gap of TiO₂ thus extending the absorption of photocatalysts to the visible regions, but also promote dramatically the separation of electron-hole pairs. Owing to these synergistic effects, the carbon coated and doped TiO₂ shows much superior photocatalytic activity for both degradation of organics and photocatalytic/photoelectrochemical (PEC) water splitting under simulated sunlight illumination. The photocatalytic activity of obtained materials can reach 5, 4 and 2 times higher than that of pristine TiO₂, carbon doped TiO₂ and carbon coated TiO₂, respectively in the degradation of organic pollutants. The carbon coated and doped TiO₂ materials exhibited more than 37 times and hundreds of times photocurrent enhancement under simulated sunlight and visible light, respectively compared to that of pristine TiO₂. The present work providing new comprehensive understanding on carbon coating and doping effect could be very helpful for the development of advanced TiO₂ materials for a large series of applications.