Dual-Functional Photocatalytic and Photoelectrocatalytic Systems for Energy- and Resource-Recovering Water Treatment

Abstract

The solar-driven photo(electro)catalytic process is a key technology for utilization of solar energy. It is being intensively investigated for application to environmental remediation and solar fuel production. Although both environmental and energy applications operate on the basis of the same principle of photoinduced interfacial charge transfer, most previous studies have focused on either the environmental or energy process only since these two processes require very different catalyst properties and reaction conditions. This Perspective describes a dualfunctional photo(electro)catalytic process that enables water treatment along with the simultaneous recovery of energy (e.g., H 2 and H 2 O 2 ) or resources (e.g., metal ions) and discusses the status and perspectives of this emerging technology. The essential feature of the process is to utilize the hole oxidation power for the degradation of water pollutants and the electron reduction power for the recovery of energy and resources from wastewaters at the same time. Various PC, PEC, and photovoltaic-driven electrochemical (PV-EC) processes with different dual-functional purposes (e.g., pollutant removal combined with H 2 or H 2 O 2 production, heavy-metal recovery, denitrification, fuel cell) are introduced and discussed. The reviewed technology should offer chances for the development of next-generation water treatment processes based on the water−solar energy nexus.

In-situ fabrication SnO2/SnS2 heterostructure for boosting the photocatalytic degradation of pollutants

“…Photocatalysis, a promising green catalysis technology, was widely investigated to address environmental pollution and mitigate energy shortage [1][2][3][4][5][6]. The use of solar-driven photocatalysts could effectively promote organic pollutant degradation.…”

Assessment of Photocatalytic Hydrogen Production from Biomass or Wastewaters Depending on the Metal Co-Catalyst and Its Deposition Method on TiO2

“…Photocatalytic valorization is particularly interesting if it is capable of transforming waste into energy or chemicals by using only sunlight as the promoter [24,25]. Applied to biomass photoreforming, it is relevant for agricultural waste materials, which are generally burned for heat value or buried in landfills.…”

Recent progress in Bi2WO6‐Based photocatalysts for clean energy and environmental remediation: Competitiveness, challenges, and future perspectives

“…[ 1 ] Since the discovery of the Fujishima and Honda effect in 1972, semiconductors photocatalysis has been greatly studied in academics and industry. [ 2,3 ] This technology can realize what human beings urgently desire, such as water splitting, [ 4–11 ] pollutant degradation, [ 12–17 ] CO 2 reduction, [ 18–25 ] and the selective synthesis of organic compounds. [ 26–29 ] Nevertheless, the following obstacles limit the practical application of semiconductor photocatalytic technology: (I) poor visible light absorption, (II) difficulty in separation of photogenerated carriers, and (III) unsatisfactory energy utilization efficiency.…”

“…[ 30,40 ] Importantly, it has promoted photocatalytic applications because of its low cost, nontoxicity, and excellent thermal and chemical stability. [ 3–28 ]…”