Facet-engineered TiO2 drives photocatalytic activity and stability of supported noble metal clusters during H2 evolution

Abstract

Nanoparticles; Photocatalysis

Nanopartículas; Fotocatálisis

Nanopartícules; Fotocatàlisi

Metal clusters supported on TiO2 are widely used in many photocatalytic applications, including pollution control and production of solar fuels. Besides high photoactivity, stability during the photoreaction is another essential quality of high-performance photocatalysts, however systematic studies on this attribute are absent for metal clusters supported on TiO2. Here we have studied, both experimentally and with first-principles simulation methods, the stability of Pt, Pd and Au clusters prepared by ball milling on nanoshaped anatase nanoparticles preferentially exposing {001} (plates) and {101} (bipyramids) facets during the photogeneration of hydrogen. It is found that Pt/TiO2 exhibits superior stability than Pd/TiO2 and Au/TiO2, and that {001} facet-based photocatalysts always are more stable than their {101} analogous regardless of the considered metal species. The loss of stability associated with cluster sintering, which is facilitated by the transfer of photoexcited carriers from the metal species to the neighbouring Ti and O atoms, most significantly and detrimentally affects the H2-evolution photoactivity.

This work was supported by projects MICINN/FEDER PID2021-124572OB-C31 and GC 2021 SGR 01061. Y.C. (CSC No. 201806920042) acknowledges the China Scholarship Council for Ph.D. scholarship support. L.S. and C.C. are grateful to MICINN Ramon y Cajal program for individual fellowship grant agreements RYC2019-026704-I and RYC2018-024947-I, respectively. J.L. is a Serra Húnter Fellow and is grateful to ICREA Academia program. N.G.B. and V.P. acknowledge financial support from RTI2018-099965-B-I00, AEI/FEDER,UE and 2017-SGR-1431. ICN2 is supported by the Severo Ochoa program from Spanish MINECO (SEV-2017-0706) and is funded by the CERCA Programme/Generalitat de Catalunya. The authors thank E. Molins, I. Matas and M. Benito from ICMAB to kindly analyze BET areas.