Dimensional engineering of covalent organic frameworks derived carbons for electrocatalytic carbon dioxide reduction

Covalent organic frameworks(COFs)have been developed as the precursors to construct porous carbons for electrocatalytic systems.However,the influences of carbon dimensions on the catalytic performance are still underexplored.In this work,we have first constructed COF-derived carbons by template-synthesis strategy in different dimensions to catalyze the carbon dioxide reduction(CO_(2)RR).By using different templates,the one-dimensional(1D),two-dimensional(2D),and three-dimensional(3D)COF-derived carbons have been employed to anchor Co-porphyrin to form the Co-N5 sites to catalyze CO_(2)RR.The 1D catalyst templated by carbon nano tubes presents high binding ability of CO_(2),more defective sites,and higher electronic conductivity,resulting in a higher catalytic activity for CO_(2)and selectivity of CO than 2D and 3D carbon-based catalysts.The 1D catalyst delivers the turnover frequency values of 1150 h^(−1)and the FECO of 94.5%at 0.7 V versus RHE,which is significantly better than those of 2D and 3D carbon-based catalysts.

Transition metal dichalcogenide-based mixed-dimensional heterostructures for visible-light-driven photocatalysis:Dimensionality and interface engineering

Two-dimensional(2D)transition metal dichalcogenides(TMDCs)are emerging as promising building blocks of high-performance photocatalysts for visible-light-driven water splitting because of their unique physical,chemical,electronic,and optical properties.This review focuses on the fundamentals of 2D TMDC-based mixed-dimensional heterostructures and their unique properties as visible-light-driven photocatalysts from the perspective of dimensionality and interface engineering.First,we discuss the approaches and advantages of surface modification and functionalization of 2D TMDCs for photocatalytic water splitting under visible-light illumination.We then classify the strategies for improving the photocatalytic activity of 2D TMDCs via combination with various low-dimensional nanomaterials to form mixed-dimensional heterostructures.Further,we highlight recent advances in the use of these mixed-dimensional heterostructures as high-efficiency visible-light-driven photocatalysts,particularly focusing on synthesis routes,modification approaches,and physiochemical mechanisms for improving their photoactivity.Finally,we provide our perspectives on future opportunities and challenges in promoting real-world photocatalytic applications of 2D TMDC-based heterostructures.

Methylammonium-and bromide-free perovskites enable efficient and stable photovoltaics

Hybrid perovskite solar cell(PSC)has attracted extensive research interest due to its rapid increase in efficiency,regarding as one of the most promising candidates for the next-generation photovoltaic technology.The certified power conversion efficiency of the devices based on formamidinium lead iodide(FAPbI_(3))perovskite has reached 25.5%,approaching the record of monocrystalline silicon solar cells.Unfortunately,the blackα-phase FAPbI_(3)materials can spontaneously transform to non-optically activeδ-phase at room temperature,which greatly hinder their photovoltaic application.In order to overcome this problem,various strategies,especially introducing methylammonium(MA^(+)),caesium(Cs^(+))and bromide(Br^(-))ions into the materials,have been widely adopted.However,MA^(+)can largely reduce the thermal stability of the materials.Furthermore,the introduction of Br^(-)can enlarge the materials'bandgap,resulting in a reduced theoretical efficiency.Keeping these in mind,developing the strategies which without using MA^(+)and Br^(-)is the inevitable trend.Here,we focus on the recent progresses of stabilizingαFAPbI_(3)without employing MA^(+)and Br^(-),and discuss the advantages of inorganic ions doping and dimensionality engineering to stabilizedαFAPbI_(3).Meanwhile,in order to deeply understand the relationship between the semiconducting properties and device performance of the corresponding materials,we then summarize several significant strategies to suppress the non-radiation recombination,such as interface modification and trap passivation.Finally,we propose to develop more effective'A-site'alternatives to stabilizeαFAPbI_(3),which is expected to achieve high-efficient PSCs with long-term stability,facilitating its commercialization process.