Vol.:(0123456789) Topics in Current Chemistry (2019) 377:24 https://doi.org/10.1007/s41061-019-0248-1 1 3 REVIEW Characterization of Photo‑catalysts: From Traditional to Advanced Approaches Uriel Caudillo‑Flores 1  · Irene Barba‑Nieto 1  · Mario J. Muñoz‑Batista 2  · Anna Kubacka 1  · Marcos Fernández‑García 1 Received: 2 March 2019 / Accepted: 16 August 2019 © Springer Nature Switzerland AG 2019 Abstract The article provides an overview of the most relevant characterization results of het- erogeneous photo-catalytic materials available in the literature. First, we present a summary of the ex situ utilization of physico-chemical characterization techniques. In the majority of current works, pre and post-reaction samples are subjected to ex situ analysis using a multitechnique approach which attempts to render informa- tion about the morphological, structural, and electronic properties of relevance to interpret photoactivity. Details of the efects on physico-chemical observables of the nanostructure and the complex chemical nature (considering mono and multiphase materials with presence of several chemical elements) of typical photo-catalysts will be analyzed. Modern studies however emphasize the use of in situ tools in order to establish activity–structure links. To this end, the frst point to pay attention to is to consider carefully the interaction between light and matter at the reaction cell where the characterization is carried out. Operando and spectro-kinetic methodologies will be reviewed as they would render valuable and trusting results and thus will pave the way for the future developments in photocatalysis. Keywords Spectroscopy · Kinetics · In situ · Operando · Spectro-kinetic · Multitechnique approach This article is part of the Topical Collection “Heterogeneous Photocatalysis”; edited by Mario J. Muñoz-Batista, Alexander Navarrete Muñoz and Rafael Luque. * Anna Kubacka ak@icp.csic.es * Marcos Fernández-García mfg@icp.csic.es 1 Instituto de Catálisis y Petroleoquímica CSIC, Marie Curie 2, 28049 Madrid, Spain 2 Departamento de Química Orgánica, Universidad de Córdoba, Edif. Marie Curie, Ctra Nnal IV-A, Km 396, 14014 Córdoba, Spain