In situ Stabilization of Au and Co Nanoparticles in a Redox-Active Conjugated Microporous Polymer Matrix: Facile Heterogeneous Catalysis and Electrocatalytic Oxygen Reduction Reaction Activity

Abstract

We report a novel in situ method for synthesis of metal nanoparticles (NPs)−CMP (conjugated microporous polymer) composites based on a redoxactive, donor−acceptor CMP, tris-(4-aminophenyl)amine (TPA)−perylenediimide (PDI). The TPA−PDI CMP, comprising triphenylamine as an electron donor and PDI as an acceptor, showed stable charge-separated state and semiconducting behavior. Further, TPA−PDI CMP has been exploited for in situ stabilization of metal (Au and Co) NPs, and two novel nanocomposites (Au@TPA−PDI and Co@TPA− PDI) were prepared. The catalytic reduction of nitro aryls to amino aryls was studied using Au@TPA−PDI, which showed excellent yields and fast kinetics. The CMP itself was found to show good activity as a metal-free oxygen reduction reaction (ORR) electrocatalyst with an onset potential of 0.82 V. Stabilizing merely 2.56 wt % Co nanoparticles in the CMP matrix improved the electrochemical ORR activity of as-synthesized TPA−PDI immensely and showed an onset potential of 0.91 V, which has also been supported by density functional theory (DFT) calculations.

Bimodal Heterogeneous Functionality in Redox‐Active Conjugated Microporous Polymer toward Electrocatalytic Oxygen Reduction and Photocatalytic Hydrogen Evolution

“…Recently, the design of redox‐active CMP materials by integrating electron‐donor and ‐acceptor organic struts has drawn immense interest, as they have shown potential for catalyzing the electrochemical oxygen reduction reaction (ORR), which is a half‐cell reaction in fuel cells and metal–air batteries . Moreover, redox‐active CMPs were also found to be capable of in situ generation and stabilization of metal nanoparticles (NPs), and subsequently, such metal nanoparticle stabilized CMP (NP@CMP) materials have shown significantly improved electrocatalytic activities . Furthermore, organic porous materials have been explored recently as heterogeneous catalysts for the photochemical H 2 evolution reaction .…”

“…[33][34][35][36][37][38] Conjugated microporous polymers( CMPs) are an emerging class of porous organic materials, which have demonstrated a treasuret rove of applications. [39,40] Owing to their synthetic diversitya nd permanent microporosity,C MP materials have gainedw idespread attention in the realmso fe nergy materials, [41,42] heterogeneousc atalysis, and luminescent materials. [35,[43][44][45][46][47] Recently,t he design of redox-activeC MP materials by integratingelectron-donora nd -acceptor organic strutsh as drawnimmense interest, as they have shownp otential forc atalyzingt he electrochemical oxygen reduction reaction (ORR), [22,41] which is ah alf-cell reactioni nf uel cells and metalair batteries.…”

“…[39,40] Owing to their synthetic diversitya nd permanent microporosity,C MP materials have gainedw idespread attention in the realmso fe nergy materials, [41,42] heterogeneousc atalysis, and luminescent materials. [35,[43][44][45][46][47] Recently,t he design of redox-activeC MP materials by integratingelectron-donora nd -acceptor organic strutsh as drawnimmense interest, as they have shownp otential forc atalyzingt he electrochemical oxygen reduction reaction (ORR), [22,41] which is ah alf-cell reactioni nf uel cells and metalair batteries. [6,28] Moreover,r edox-activeC MPs were also found to be capable of in situ generation and stabilizationo fm etal nanoparticles (NPs), and subsequently,s uch metal nanoparticle stabilized CMP (NP@CMP) materials have shown significantly improvede lectrocatalytic activities.…”

“…[6,28] Moreover,r edox-activeC MPs were also found to be capable of in situ generation and stabilizationo fm etal nanoparticles (NPs), and subsequently,s uch metal nanoparticle stabilized CMP (NP@CMP) materials have shown significantly improvede lectrocatalytic activities. [22,41] Furthermore, organic porousm aterials have been exploredr ecently as heterogeneous catalysts for the photochemical H 2 evolution reaction. [48][49][50][51][52][53][54] However, improvements in both these processes in ac ost-effectivem anner are importantc hallenges for the scientificc ommunity.…”

Heterocyclization Strategy for Construction of Linear Conjugated Polymers: Efficient Metal‐Free Electrocatalysts for Oxygen Reduction

“…These values are among the highest values reported for the ORR with metal-free polymers as catalysts and without the process of pyrolysis and heteroatom doping. [10][11][12][13][14][15][16][17] DFT calculations reveal that the combined structure of N-and Sheterocycles is the key to developing novel electrocatalysts with distinct chemical compositions and molecular structures for efficient ORR catalytic activity.…”