Computational Design of Single Mo Atom Anchored Defective Boron Phosphide Monolayer as a High-performance Electrocatalyst for the Nitrogen Reduction Reaction

Catalytic reduction of molecular dinitrogen(N_(2))to ammonia(NH_(3))is one of the most important and challenging industrial reactions.Electrochemical reduction is considered as an energy-saving technology for artificial ambient nitrogen fixation,which is emerging as an optimal potential sustainable strategy to substitute for the Haber–Bosch process.However,this process demands efficient catalysts for the N_(2)reduction reaction(NRR).Here,by means of first-principles calculations,we systematically explored the potential electrocatalytic performance of single transition metal atoms(Pd,Ag,Rh,Cu,Ti,Mo,Mn,Zn,Fe,Co,Ru,and Pt)embedded in monolayer defective boron phosphide(TMs/BP)monolayer with a phosphorus monovacancy for ambient NH_(3)production.Among them,the Mo/BP exhibits the best catalytic performance for ambient reduction of N_(2)through the typical enzymatic and consecutive reaction pathways with an activation barrier of 0.68 e V,indicating that Mo/BP is an efficient catalyst for N_(2)fixation.We believe that this work could provide a new avenue of ambient NH_(3)synthesis by using the designed single-atom electrocatalysts.

Nanovoid-confinement and click-activated nanoreactor for synchronous delivery of prodrug pairs and precise photodynamic therapy

Bioorthogonal cleavage reaction-triggered prodrug activation by the pretargeted methods can achieve accurate cancer therapy.However,the click and release efficiency of these methods in vivo is limited by the space-time dislocation of bioorthogonal prodrug-trigger pairs within the tumor area,caused by their asynchronous administration and inconsistent accumulation for most delivery systems.We herein created a nanovoid-confinement and click-activated(NCCA)core–shell nanoreactor by incorporating prodrugs within zeolitic imidazolate framework-90(ZIF-90)as core and coating tetrazine-based covalent organic framework(COF)as shell.After surface modification of aptamer polymer,the NCCA nanoreactor enabled the sufficient delivery of photodynamic prodrugs within tumor.Notably,the core of ZIF-90 was decomposed by tumor acidic environment,inducing the high-efficiency activation of photodynamic prodrugs via nanoconfined bioorthogonal reaction with tetrazine-based COF shell.As a result,such photodynamic agents are efficiently and safely accumulated into tumor and specifically activated for precise photodynamic therapy of cancer cells and tumor bearing mice with minimizing toxic side effect.Taken together,such NCCA nanoreactor clearly demonstrates the critical feasibility to realize the synchronous delivery of both prodrugs and triggers for precise treatment,which most of delivery systems are not able to afford.