Tailoring electrocatalytic activity of in situ crafted perovskite oxide nanocrystals via size and dopant control

Favoring Product Desorption by a Tailored Electronic Environment of Oxygen Vacancies in SrTiO3 via Cr Doping for Enhanced and Selective Electrocatalytic CO2 to CO Conversion

The electrochemical CO₂ reduction reaction (ECO₂RR) into value-added products is crucial to address the herculean task of CO₂ mitigation. Several efforts are being made to develop active ECO₂RR catalysts, targeting enhanced CO₂ adsorption and activation. A rational design of ECO₂RR catalysts with a facile product desorption step is seldom reported. Herein, ensuing the Sabatier principle, we report a strategy for an enhanced ECO₂RR with a faradaic efficiency of 85% for CO production by targeting the product desorption step. The energy barrier for product desorption was lowered via a tailored electronic environment of oxygen vacancies (O_vac) in Cr-doped SrTiO₃. The substitutional doping of Cr³⁺ for Ti⁴⁺ into the SrTiO₃ lattice favors the generation of more O_vac and modifies the local electronic environment. Density functional theory analysis evinces the spontaneous dissociation of COOH^# intermediates over O_vac and lower CO intermediate binding on O_vac reducing the energy demand for CO release due to Cr doping.

Introduction of Surface Modifiers on the Pt-Based Electrocatalysts to Promote the Oxygen Reduction Reaction Process

The design of Pt-based electrocatalysts with high efficiency towards acid oxygen reduction reactions is the priority to promote the development and application of proton exchange membrane fuel cells. Considering that the Pt atoms on the surfaces of the electrocatalysts face the problems of interference of non-active species (such as OH_ad, OOH_ad, CO, etc.), high resistance of mass transfer at the liquid-solid interfaces, and easy corrosion when working in harsh acid. Researchers have modified the surfaces' local environment of the electrocatalysts by introducing surface modifiers such as silicon or carbon layers, amine molecules, and ionic liquids on the surfaces of electrocatalysts, which show significant performance improvement. In this review, we summarized the research progress of surface modified Pt-based electrocatalysts, focusing on the surface modification strategies and their mechanisms. In addition, the development prospects of surface modification strategies of Pt-based electrocatalysts and the limitations of current research are pointed out.

Electronic Modulation of Metal-Organic Frameworks Caused by Atomically Dispersed Ru for Efficient Hydrogen Evolution

Designing excellent electrocatalysts for the hydrogen evolution reaction (HER) is extremely significant in producing clean and sustainable hydrogen fuel. Herein, a rational strategy is developed to fabricate a promising electrocatalyst by introducing atomically dispersed Ru into a cobalt-based metal-organic framework (MOF), Co-BPDC (Co(bpdc)(H₂ O)₂ , BPDC: 4,4'-Biphenyldicarboxylic acid). The obtained CoRu-BPDC nanosheet arrays exhibit remarkable HER performance with an overpotential of 37 mV at a current density of 10 mA cm^-2 in alkaline media, which is superior to most of the MOF-based electrocatalysts and comparable to the commercial Pt/C. Synchrotron radiation-based X-ray absorption fine structure (XAFS) spectroscopy studies verify that the isolated Ru atoms are dispersed in Co-BPDC nanosheets with the formation of five-coordinated Ru-O₅ species. XAFS spectroscopy combined with density functional theory (DFT) calculations unravels that atomically dispersed Ru can modulate the electronic structure of the as-obtained Co-BPDC, contributing to the optimization of binding strength for H* and the enhancement of HER performance. This work opens a new avenue to rationally design highly-active single-atom modified MOF-based HER electrocatalysts via modulating electronic structures of MOF.

Tailoring Charge Separation at Meticulously Engineered Conjugated Polymer/Perovskite Quantum Dot Interface for Photocatalyzing Atom Transfer Radical Polymerization

In stark contrast to conventional organic ligand-capped counterparts, the ability to create stable metal halide perovskite nanocrystals strongly tethered with conjugated polymers (CPs) represents an important endeavor toward tailoring charge carrier dynamics at their interface that critically underpins applications of this unique class of all semiconducting, organic-inorganic nanomaterials for optoelectronics. This, however, has yet to be largely explored. Herein, we report, for the first time, the unraveling of efficient charge separation at judiciously designed CP/perovskite quantum dot (QD) interface for photoinduced atom transfer radical polymerization (p-ATRP). Such scrutiny is rendered by in situ crafting an array of monodisperse, highly stable, CP-ligated perovskite QDs with precisely controlled dimensions of each constituent via capitalizing on unimolecular, amphiphilic starlike block copolymers as nanoreactors. The intimate and permanent surface tethering of CPs imparts remarkable thermal, photo, and polar solvent stabilities of CP-ligated perovskite QDs. More importantly, they manifest efficient interfacial charge separation with a profound dependence on the length of ligated CPs and the size of perovskite QDs. The outstanding structural stabilities and charge separation characteristic enable CP-ligated perovskite QDs as robust photocatalysts for p-ATRP of a wide selection of monomers with stable and controllable reaction kinetics, also depending crucially on the length of CPs and the size of perovskite QDs. In principle, an exciting variety of CP-ligated, uniform perovskite QDs with virtually unlimited material choice of both markedly improved stabilities and tunable electronic band alignments can be readily accessed by exploiting the amphiphilic starlike block copolymer nanoreactor strategy for use in photodetectors, sensors, and LEDs, among other areas.