"The concept of utilizing water splitting to provide H2 was proposed as early as the time of Jules Verne.1 In 1972, the Honda and Fujishima results2,3 suggested that such a dream is achievable. Based on Bard’s concept4 that when the semiconductor electrode and metal counter electrode have been brought into contact in
single particle, it can be pictured as a “short-circuited” photoelectrochemical cell. As a method for the direct conversion of photon energy to chemical energy and for energy storage similar to photosynthesis, the photocatalytic hydrogen production from water using semiconductor photocatalysts has been investigated in considerable detail.5,6 Recently, doping TiO2 with nonmetal atoms has received a lot of attention.7-14 Zhao found that doping improvement of oxidation properties of TiO2 for organics under visible irradiation.13a In the meantime, Li found Be doping could enhance the photocatalytic hydrogen generation rate with electron donors.13b Salt lakes are widely distributed and easily available on the earth, in which borate was concentrated to a very high bulk concentration especially to a super-saturation and existed mainly in the form of tetraborate B4O7 2-. Since reduction properties variation of TiO2 by boron doping is lacking and important impact of hydrogen generation via solar irradiation, we carried out a detailed investigation of the effect of borate doping on the reduction properties of H2O to H2 on TiO2. In the present study, we report a new photocatalyst, Ptx-/TiO2-yBy, prepared by impregnation of the B4O7 2- anion on TiO2. Our findings indicate that incorporationof B into Pt/TiO2 results in a negative shift of Pt binding energy and the efficient reduction of H+ to H2 even in the absence of sacrificial electron donors. It was found that the B4O7 2- anion in solution is an efficient promoter for water reduction. Moreover, it was found that the interval illumination might enhance the rate of hydrogen evolution...."
From the upcoming issue of
Energy and Fuels.
http://pubs.acs.org/cgi-bin/abstract.cgi/enfuem/asap/abs/ef049697q.html