Temperature‐ and pH‐Responsive Polymeric Photocatalysts for Enhanced Control and Recovery

Abstract

The emergence of heterogeneous photocatalysis has facilitated redox reactions with high efficiency, without compromising the recyclability of the photocatalyst. Recently, stimuli‐responsive heterogeneous photocatalytic materials have emerged as a powerful synthetic tool, with simple and rapid recovery, as well as an enhanced dynamic control over reactions. Stimuli‐responsive polymers are often inexpensive and easy to produce. They can be switched from an active “on” state to an inert “off” state in response to external stimuli, allowing the production of photocatalyst with adaptability, recyclability, and orthogonal control on different chemical reactions. Despite this versatility, the application of artificial smart material in the field of heterogeneous photocatalysis has not yet been maximized. In this Minireview, we will examine the recent developments of this emerging class of stimuli‐responsive heterogeneous photocatalytic systems. We will discuss the synthesis route of appending photoactive components into different triggerable systems and, in particular, the controlled activation and recovery of the materials.

Ultra-high molecular weight complex coacervates via polymerization-induced electrostatic self-assembly

“…Polymers generated through RDRP have been widely adopted for various applications, from photocatalysis to drug/gene delivery. 1–5 Some critical reasons for the growth and popularity of these systems have been their ease of synthesis, high functional group tolerance, and the ability to control dispersity and generate various block copolymer (BCP) architectures. 6…”

Thermoresponsive polymer brush photocatalytic substrates for wastewater remediation

“…Multi-responsive photoactive polymers are an intriguing and effective approach towards photocatalysis. 20,34,35 Such systems provide tunable photocatalytic activity in response to a second stimulus – e.g. , pH, 36 addition of CO 2 , 37 or temperature 38 – which expands and/or contracts the catalyst-surrounding matrix or modifies its chemical environment.…”

“…Amongst these are (i) their expensive nature, (ii) limited solubility in aqueous media due to their aromatic skeletons, and (iii) challenges in their separation from the treated water. 20 These constraints have motivated research into heterogeneous photocatalysts, which has become the most broadly studied method to leverage photocatalysts in wastewater treatment. 13,14,16,17,20,21 For example, metal oxides (e.g.…”

“…20 These constraints have motivated research into heterogeneous photocatalysts, which has become the most broadly studied method to leverage photocatalysts in wastewater treatment. 13,14,16,17,20,21 For example, metal oxides (e.g. TiO 2 or ZnO) composite photocatalysts have been extensively studied as in the removal of pollutants.…”

“…Multi-responsive photoactive polymers are an intriguing and effective approach towards photocatalysis. 20,34,35 Such systems provide tunable photocatalytic activity in response to a second stimuluse.g., pH, 36 addition of CO 2 , 37 or temperature 38 which expands and/or contracts the catalyst-surrounding matrix or modifies its chemical environment. Proof-ofconcept studies exist on how the activity of a network-incorporated photocatalyst can be modulated by modifying steric access to the active sites through external stimuli.…”