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It is of broad interest to develop emerging photocatalysts with excellent light-harvesting capacity and high charge carrier separation efficiency for visible light photocatalytic hydrogen evolution reaction. However, achieving satisfying hydrogen evolution efficiency under noble metal-free conditions remains challenging. In this study, we demonstrate the fabrication of three-dimensionally ordered macroporous SrTiO3 decorated with ZnxCd1−xS nanoparticles for hydrogen production under visible light irradiation (λ > 420 nm). Synergetic enhancement of photocatalytic activity is achieved by the slow photon effect and improved separation efficiency of photogenerated charge carriers. The obtained composites could afford very high hydrogen production efficiencies up to 19.67 mmol·g−1·h−1, with an apparent quantum efficiency of 35.9% at 420 nm, which is 4.2 and 23.9 times higher than those of pure Zn0.5Cd0.5S (4.67 mmol·g−1·h−1) and CdS (0.82 mmol·g−1·h−1), respectively. In particular, under Pt-free conditions, an attractive hydrogen production rate (3.23 mmol·g−1·h−1) was achieved, providing a low-cost and high-efficiency strategy to produce hydrogen from water splitting. Moreover, the composites showed excellent stability, and no obvious loss in activity was observed after five cycling tests. [ABSTRACT FROM AUTHOR]

The pyrolytic activated carbon derived from waste tires (PTC) was functionalized to fabricate the high performance of Pt-based catalysts in the dehydrogenation of methylcyclohexane and hydrogen production. Structural characterizations evidenced that the modification partially influenced the surface area, the pore structure, and the oxygen-containing functional groups of the supports. The techniques of CO pulse, transmission electron microscopy, and hydrogen temperature-programmed reduction were utilized to investigate the dispersion degrees and particle sizes of the active component Pt, and its interaction with the various functionalized supports, respectively. The results manifested that Pt particles loaded on the functionalized PTC-S had the largest dispersion degree and the smallest size among those loaded on PTC and other functionalized PTC (i.e., PTC-K and PTC-NH). Finally, the Pt-based catalysts were successfully applied in the dehydrogenation reaction of methylcyclohexane to yield hydrogen. The results revealed that the Pt catalyst over the functional PTC-S support exhibited a more excellent conversion of methylcyclohexane (84.3%) and a higher hydrogen evolution rate (991.5 mmol/gPt/min) than the other resulting Pt-based catalysts. [ABSTRACT FROM AUTHOR]

Abstract: Pyrolytic waste tire char was modified to be used as support and a series of catalysts supported with 0.1–1.0 wt% Pt were prepared by conventional wetness impregnation method. TEM images show that the Pt nanoparticles are well-dispersed in any microregions in the sample view on the TEM grid. The results of methylcyclohexane dehydrogenation reaction show the Pt loadings and the reaction temperature have a significant impact on the catalytic activity. [Copyright &y& Elsevier]

New ternary composites based on three dimensionally ordered macroporous (3DOM) SrTiO 3 (CdS/Au/3DOM-SrTiO 3 ) were prepared and used as photocatalysts in visible light (λ > 420 nm) photocatalytic water splitting for hydrogen evolution. Through optimizing the pore size of 3DOM-SrTiO 3 materials and the loading amounts of Au and CdS, CdS/Au/3DOM-SrTiO 3 (300), templated by 300 nm sized poly(methyl methacrylate) colloids, was found to exhibit a remarkably enhanced photocatalytic hydrogen evolution rate (2.74 mmol/h⋅g), which was 3.2 times as high as that of CdS/Au/C-SrTiO 3 catalyst based on commercial SrTiO 3 . This notably enhanced photocatalytic performance was mainly attributed to the slow photon enhancement effect of 3DOM-SrTiO 3 (300) material, which significantly promoted the light harvesting efficiency of ternary composite for the slow photon region of 3DOM-SrTiO 3 (300) was well matched with the optical absorption band of photocatalyst. Further depositing Pt nanoparticles on CdS/Au/3DOM-SrTiO 3 (300) composite as a co-catalyst, an extraordinarily high hydrogen evolution rate (up to 5.46 mmol/g⋅h) and apparent quantum efficiency (42.2% at 420 nm) were achieved because of the synergistic effect of efficient carrier separation, Au SPR effect, and slow photon effect. Furthermore, these ternary CdS/Au/3DOM-SrTiO 3 composite photocatalysts were very stable and could be easily recycled four times in visible light photocatalytic water splitting experiments without any loss in activity. [ABSTRACT FROM AUTHOR]

Three-dimensionally ordered macroporous SrTiO 3 (3DOM-SrTiO 3 ) materials with different pore sizes were originally prepared and employed as photocatalysts in the water splitting for hydrogen generation. These 3DOM-SrTiO 3 photocatalysts were characterized by XRD, SEM, TEM, EDS, DR UV–vis and N 2 sorption. Because of the slow photon effect of 3DOM-SrTiO 3 , notably enhanced efficiency of water splitting for hydrogen evolution was obtained compared with the solid-state SrTiO 3 (SS-SrTiO 3 ) and disordered porous SrTiO 3 (Disorder-SrTiO 3 ). The effect of stop-band on the efficiency of photocatalytic hydrogen production was studied by tuning the pore diameter of 3DOM-SrTiO 3 . It was found that higher hydrogen evolution efficiency could be achieved when the photonic stop-band of 3DOM-SrTiO 3 was overlapped with its band gap, which was further confirmed by the control experiments under certain wavelength light irradiation. 3DOM-SrTiO 3 (270 nm) exhibited the highest photocatalytic hydrogen evolution rate (up to 3599 μmol/g·h), which was 31 times as high as that of SS-SrTiO 3 and 11 times higher than that of Disorder-SrTiO 3 . Furthermore, these 3DOM-SrTiO 3 catalysts were very stable and no obvious loss in photocatalytic efficiency of hydrogen production was observed after five cycles. [ABSTRACT FROM AUTHOR]

• Light-driven hydrogen treated Au/3DOM-TiO 2 catalysts are firstly synthesized. • Notably enhanced efficiency for water splitting hydrogen evolution is obtained. • The band gap engineering of as-synthesized hydrogen treated Au/3DOM-TiO 2 catalysts are effective adjusted. • The slow photon enhancement effect of hydrogen treated Au/3DOM-TiO 2 is demonstrated. As one of the most promising photocatalysts for hydrogen production from water splitting, conventional TiO 2 materials suffer from the low quantum yield and light absorption efficiency. The present study provided a strategy to improve efficiency of TiO 2 -based photocatalysts for hydrogen production from water splitting based on an interesting structure-property relationship. The hydrogen treated Au/TiO 2 photocatalysts with three-dimensionally ordered macroporous (3DOM) structure were successfully synthesized and well characterized through various methods. The 3DOM-structure and Au modification can promote the hydrogenation of TiO 2. The light absorption can be improved by slow photon effect of the 3DOM structure. And, in the meanwhile, the hydrogenation as well as Au modification can improve the photogenerated carrier separation. In addition, to understand how hydrogenation and Au modification promote electron migration and decrease carrier recombination, the electric band structure for hydrogen treated Au/3DOM-TiO 2 was well studied and we found the local electron field enhancement, surface band bending and the generation of mid-gap state contributed most of enhancement. [ABSTRACT FROM AUTHOR]