Regulating the relative content of O2− and OH for PCPNa degradation on BiOCl plates with controllable exposed crystal faces and surface oxygen vacancies

Mechanistic Insights Into H2O Dissociation in Overall Photo-/Electro-Catalytic CO2 Reduction

Photo-/electro-catalytic CO2 reduction with H2O to produce fuels and chemicals offers a dual solution to address both environmental and energy challenges. For a long time, catalyst design in this reaction system has primarily focused on optimizing reduction sites to improve the efficiency or guide the reaction pathway of the CO2 reduction half-reaction. However, less attention has been paid to designing activation sites for H2O to modulate the H2O dissociation half-reaction. Impressively, the rate-determining step in overall CO2 reduction is the latter, and it influences the evolution direction and formation energy of carbon-containing intermediates through the proton-coupled electron transfer process. Herein, we summarize the mechanism of the H2O dissociation half-reaction in modulating CO2 reduction performance based on cutting-edge research. These analyses aim to uncover the potential regulatory mechanisms by which H2O activation influences CO2 reduction pathways and conversion efficiency, and to establish a mechanism-structure-performance relationship that can guide the design and development of high-efficiency catalytic materials. A summary of advanced characterization techniques for investigating the dissociation mechanism of H2O is presented. We also discuss the challenges and offer perspectives on the future design of activation sites to improve the performance of photo-/electro-catalytic CO2 reduction.

A Comprehensive Review on the Boosted Effects of Anion Vacancy in the Heterogeneous Photocatalytic Degradation, Part II: Focus on Oxygen Vacancy

Environmental problems, including the increasingly polluted water and the energy crisis, have led to a need to propose novel strategies/methodologies to contribute to sustainable progress and enhance human well-being. For these goals, heterogeneous semiconducting-based photocatalysis is introduced as a green, eco-friendly, cost-effective, and effective strategy. The introduction of anion vacancies in semiconductors has been well-known as an effective strategy for considerably enhancing the photocatalytic activity of such photocatalytic systems, giving them the advantages of promoting light harvesting, facilitating photogenerated electron-hole pair separation, optimizing the electronic structure, and enhancing the yield of reactive radicals. This Review will introduce the effects of anion vacancy-dominated photodegradation systems. Then, their mechanism will illustrate how an anion vacancy changes the photodegradation pathway to enhance the degradation efficiency toward pollutants and the overall photocatalytic performance. Specifically, the vacancy defect types and the methods of tailoring vacancies will be briefly illustrated, and this part of the Review will focus on the oxygen vacancy (OV) and its recent advances. The challenges and development issues for engineered vacancy defects in photocatalysts will also be discussed for practical applications and to provide a promising research direction. Finally, some prospects for this emerging field will be proposed and suggested. All permission numbers for adopted figures from the literature are summarized in a separate file for the Editor.

Exploring the activation pathway of photo-induced electrons in facets-dependent I-doped BiOCl nanosheets for PCPNa degradation

Electrons can degrade pentachlorphenate sodium (PCPNa) directly or activate molecular oxygen to produce·O2-and ·OH for its degradation. However, less work has been performed to control such two kinds of reaction pathway by modifying BiOCl. Herein, we firstly regulated the reaction pathway between electrons and PCPNa by adjusting the amount of surface oxygen vacancies (OVs) and surface adsorbed hydroxyl groups in I^-doped BiOCl exposed with different facets. OVs on (001) facets-exposed I^-doped BiOCl enabled large amount of PCPNa to adsorb on its surface and facilitated the direct reaction between electrons and PCPNa. In contrary, more surface adsorbed hydroxyl groups and oxygen on (010) facets-exposed I^-doped BiOCl can retard the direct reaction between electrons and PCPNa via lowering the adsorption of PCPNa and increasing the activation of molecular oxygen by electrons. Although more·O2-and ·OH generated in I^-doped (010)-facets exposed BiOCl, I^-doped (001)-facets exposed BiOCl exhibited better photocatalytic activity. We proposed that the direct reaction between electrons and PCPNa can enhance the utilization efficiency of photogenerated electrons and improve photocatalytic degradation efficiency of PCPNa.

Regulation of surface plasmon resonance and oxygen vacancy defects in chlorine doped Bi–BiO2−x for imidacloprid photocatalytic degradation

In this work, chlorine doped Bi–BiO_2−x (Cl–Bi–BiO_2−x) was prepared by a one-step solvothermal method using sodium bismuthate (NaBiO₃·2H₂O) as a Bi source without the addition of a surfactant.