Jose C Conesa

Instituto de Catálisis y Petroleoquímica, CSIC, Spain

Title: Sulfide-based photocatalysts using visible light - A review

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Biography

J.C. Conesa entered the permanent research staff of Instituto de Catálisis y Petroleoquímica (ICP) in 1979, becoming there Research Professor in 2004. He was ICP Vicedirector from 2010 to 2014, and Director from 2014 to 2018. He is now Ad Honorem Professor.

He was first in Spain using synchrotron radiation to study heterogeneous catalysis; in CSIC using quantum calculations to study them, and in ICP using microemulsions to make oxide nanoparticles. He works in XPS and FTIR (including operando mode) and in EPR and UV-Vis-NIR spectroscopies.

He has worked on metal-support interactions, and on CeO₂-supported metals/oxides. He uses now CeO₂-based combinations for H₂ technologies. He kept always interest in photocatalysis and photoactive solids.

He belongs since 2014 to the Steering Committee of AMPEA. According to the Web of Science database, his over 200 articles and book chapters received to date more than 9700 citations, leading to a Hirsch index h=56.

Abstract

Sulphides are used frequently for photocatalysis, since they are better absorbers of visible light than oxides; indeed, in some cases they can absorb light even in the near-infrared range. Their drawback is however that they are prone to photocorrosion, mainly in oxidizing conditions; they are therefore more frequently used in reductive processes, e.g. H₂ production or CO₂ reduction to a number of fuels. Here an overview will be given of different sulphides (HgS, Cu₂S, CdS, chalcopyrites, FeS₂, MoS₂, PbS, etc.) used for different photocatalytic processes, giving details of their structures and photocatalytic action and, where appropriate, recent reviews on their behaviour. Results obtained in recent years by our group with several powder sulphides (in particular, In₂S₃, ZnIn₂S₄ and SnS₂) will be described. After giving their S_BET areas and other details, it will be shown how to determine their wavelength dependent photocatalytic activities, and in one case (In₂S₃) a detailed mechanism of its action in the degradation of the RhB dye will be explained. It will be shown as well how to modify them in order to extend their wavelength range of activity (as is the case, for example, in the intermediate band scheme), and how photocatalytic and photoelectrochemical techniques can be used, combining these sulphides with some enzymes of types hydrogenase (with a bimetallic Ni-Fe cluster as active species) or laccase (having 4 Cu ions as active species), so as to achieve the photo-splitting of water. Preliminary results on the reduction of CO₂ to formate ions, using a formate dehydrogenase enzyme containing W as active element, will be shown as well.