Ternary Pt/SnOx/TiO2 photocatalysts for hydrogen production: consequence of Pt sites for synergy of dual co-catalysts

Abstract

A variety of ternary nanoheterostructures composed of Pt nanoparticles (NPs), SnOx species, and anatase TiO2 are designed elaborately to explore the effect of interfacial electron transfer on photocatalytic H2 evolution from a biofuel-water solution. Among numerous factors controlling the H2 evolution, the significance of Pt sites for the H2 evolution is highlighted by tuning the loading procedure of Pt NPs and SnOx species over TiO2. A synergistic enhancement of H2 evolution can be achieved over the Pt/SnOx/TiO2 heterostructures formed by anchoring Pt NPs at atomically-isolated Sn-oxo sites, whereas the Pt/TiO2/SnOx counterparts prepared by grafting single-site Sn-oxo species on Pt/TiO2 show a marked decrease in the rate of H2 evolution. The characterization results clearly reveal that the synergy of Pt NPs and SnOx species originates from the vectorial electron transfer of TiO2 → SnOx → Pt occurring on the former, while the latter results from the competitive electron transfer from TiO2 to SnOx and to Pt NPs.

Structural evolution in Pt/Ga-Zn-oxynitride catalysts for photocatalytic reforming of methanol

“…As it was mentioned above, adequate activity in the photocatalytic hydrogen production could not be achieved without a metallic co-catalyst like Pt [13,18,27]. One of our main questions was whether the hydrogenation and the calcination processes, which were necessary for the formation of the co-catalyst from the impregnated precursor salt on the surface of the oxynitride, would change the semiconductor.…”

“…The H 2 formation in the methanol photocatalytic reforming reaction increases several orders of magnitude if co-catalysts have been introduced onto the surface of the semiconductor [16][17][18]. In the absence of co-catalysts, semiconductors induce poor H 2 evolution even in the presence of any sacrificial electron donor [13].…”

PtOx-SnOx-TiO2 catalyst system for methanol photocatalytic reforming: Influence of cocatalysts on the hydrogen production

“…there are relatively few reports dedicated to the characterization of the cocatalysts in the PtO xSnO x -TiO 2 photocatalytic system up to now [34][35][36]. To the best of our knowledge no systematic study of the effect of cocatalyst formation in these systems exists; only influence of redox-treatment on Pt/TiO 2 system has been described [37].…”

SnO2-core carbon-shell composite nanotubes with enhanced photocurrent and photocatalytic performance

“…In particular, it has been demonstrated successfully by different groups including ours that growing a layer of carbon on the surface of metal oxides improves http://dx.doi.org/10.1016/j.apcatb.2014. 11.031 0926-3373/© 2014 Elsevier B.V. All rights reserved. their photocatalytic properties.…”

“…Thus, some attempts have been made to reduce the recombination of photoinduced electron-hole pairs and to widen its utilization of solar light for photocatalysis, by decorating the photocatalysts with carrier scavenging agents such as noble metals (e.g. Au, Ag), metal oxides with narrower bandgaps and organic molecules [9][10][11].…”