Mo_(2)P Monolayer as a Superior Electrocatalyst for Urea Synthesis from Nitrogen and Carbon Dioxide Fixation:A Computational Study

Urea synthesis through the simultaneous electrocatalytic reduction of N_(2)and CO_(2)molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production,in which the development of stable,highly efficient,and highly selective catalysts to boost the chemisorption,activation,and coupling of inert N_(2)and CO_(2)molecules remains rather challenging.Herein,by means of density functional theory computations,we proposed a new class of two-dimensional nanomaterials,namely,transition-metal phosphide monolayers(TM_(2)P,TM=Ti,Fe,Zr,Mo,and W),as the potential electrocatalysts for urea production.Our results showed that these TM_(2)P materials exhibit outstanding stability and excellent metallic properties.Interestingly,the Mo_(2)P monolayer was screened out as the best catalyst for urea synthesis due to its small kinetic energy barrier(0.35 eV)for C-N coupling,low limiting potential(-0.39 V),and significant suppressing effects on the competing side reactions.The outstanding catalytic activity of the Mo_(2)P monolayer can be ascribed to its optimal adsorption strength with the key^(*)NCON species due to its moderate positive charges on the Mo active sites.Our findings not only propose a novel catalyst with high-efficiency and high-selectivity for urea production but also further widen the potential applications of metal phosphides in electrocatalysis.

Ultrathin origami accordion-like structure of vacancy-rich graphitized carbon nitride for enhancing CO_(2) photoreduction

Retaining the ultrathin structure of two-dimensional materials is very important for stabilizing their catalytic performances.However,aggregation and restacking are unavoidable,to some extent,due to the van der Waals interlayer interaction of two-dimensional materials.Here,we address this challenge by preparing an origami accordion structure of ultrathin twodimensional graphitized carbon nitride(oa-C_(3)N_(4))with rich vacancies.This novel structured oa-C_(3)N_(4) shows exceptional photocatalytic activity for the CO_(2) reduction reaction,which is 8.1 times that of the pristine C_(3)N_(4).The unique structure not only prevents restacking but also increases light harvesting and the density of vacancy defects,which leads to modification of the electronic structure,regulation of the CO_(2) adsorption energy,and a decrease in the energy barrier of the carbon dioxide to carboxylic acid intermediate reaction.This study provides a new avenue for the development of stable highperformance two-dimensional catalytic materials.

N-heterocyclic carbene as a promising metal-free electrocatalyst with high efficiency for nitrogen reduction to ammonia

Electrocatalytic nitrogen reduction reaction(NRR)at ambient conditions holds great promise for sustainably synthesizing ammonia(NH3),while developing highly-efficient,long-term stable,and inexpensive catalysts to activate the inert N≡N bond is a key scientific issue.In this work,on the basis of the concept"N-heterocyclic carbenes(NHCs)",we propose a carbon decorated graphitic-carbon nitride(C/g-C3N4)as novel metal-free NRR electrocatalyst by means of density functional theory(DFT)computations.Our results reveal that the introduced C atom in g-C3N4 surface can be regarded as NHCs and catalytic sites for activating N≡N bond,and are stabilized by the g-C3N4 substrate due to sterically disfavored dimerization.Especially,this NHCs-based heterogeneous catalysis can efficiently reduce the activated N2 molecule to NH3 with a low overpotential of 0.05 V via an enzymatic mechanism.Our work is the first report of NHCs-based electrocatalyst for N2 fixation,thus opening an alternative avenue for advancing sustainable NH3 production.

Tuning precise numbers of supported nickel clusters on graphdiyne for efficient CO_(2)electroreduction toward various multi-carbon products

Compared to single-atom catalysts,supported metal clusters can exhibit enhanced activity and designated selectivity in heterogeneous catalysis due to their unique geometric and electronic features.Herein,by means of comprehensive density functional theory (DFT) computations,we systematically investigated the potential of several Ni clusters supported on graphdiyne (Ni_(x)/GDY,x=1–6) for CO_(2) reduction reaction (CO_(2)RR).Our results revealed that,due to the strong interaction between Ni atoms and sp-hybridized C atoms,these supported Ni clusters on GDY exhibit high stabilities and excellent electronic properties.In particular,according to the computed free energy profiles for CO_(2)RR on these Ni_(x)/GDY systems,the anchored Ni_(4) cluster was revealed to exhibit high CO_(2)RR catalytic activity with a small limiting potential and moderate kinetic barrier for C–C coupling,and CH_(4),C_(2)H_(5)OH,and C_(3)H_(7)OH were identified as the main products,which can be attributed to its strong capacity for CO_(2) activation due to its unique configuration and excellent electronic properties.Thus,by carefully controlling the precise numbers of atoms in sub-nano clusters,the spatially confined Ni clusters can perform as promising CO_(2)RR catalysts with high-efficiency and high-selectivity,which may provide a useful guidance to further develop novel and low-cost metal clusters-based catalysts for sustain CO_(2)conversion to valuable chemicals and fuels.

Single-atom rhodium anchored on S-doped black phosphorene as a promising bifunctional electrocatalyst for overall water splitting

Superior bifunctional electrocatalysts with ultra-high stability and excellent efficiency are crucial to boost the oxygen evolution reaction(OER) and the hydrogen evolution reduction(HER) in the overall water splitting(OWS) for the sustainable production of clean fuels. Herein, comprehensive density functional theory(DFT) computations were performed to explore the potential of several single transition metal(TM) atoms anchored on various S-doped black phosphorenes(TM/Snx-BP) for bifunctional OWS electrocatalysis. The results revealed that these candidates display good stability, excellent electrical conductivity, and diverse spin moments. Furthermore, the Rh/S12-BP catalyst was identified as an eligible bifunctional catalyst for OWS process due to the low overpotentials for OER(0.43 V) and HER(0.02 V), in which Rh and its adjacent P atoms were identified as the active sites. Based on the computed Gibbs free energies of OH~*, O~*, OOH~* and H~*, the corresponding volcano plots for OER and HER were established.Interestingly, the spin moments and the charge distribution of the active sites determine the catalytic trends of OER and HER. Our findings not only propose a promising bifunctional catalyst for OWS, but also widen the potential application of BP in electrocatalysis.

Epidemiological Data of Work-Related Musculoskeletal Disorders—China,2018–2020

Summary What is already known about this topic?In recent decades,work-related musculoskeletal disorders(WMSDs)have become increasingly prominent and have become an important issue that is of universal concern and an urgent need to be solved in all countries of the world.What is added by this report?The top three industries or occupational groups with the highest standardized prevalence rate of WMSDs were flight attendants,medical staff,and vegetable greenhouses in that order.Women workers were 1.5 times more likely to suffer from WMSDs than men workers.

Investigation on Work-Related Musculoskeletal Disorders--China, 2018−2019

What is already known about this topic?Work-related musculoskeletal disorders(WMSDs)have a high prevalence and seriously harmful,which has attracted extensive attention in various countries in the world.Currently,the occurrence and rules of WMSDs in key industries are not known in China.What is added by this report?The prevalence of WMSDs is relatively high among professional populations in key industries in China,with the most commonly affected body parts concentrated in neck,shoulders,and low back and increasing with age and working years.What are the implications for public health practice?This study determined the prevalence and distribution characteristics of WMSDs in key industries in China and provided scientific evidence to recommend for inclusion of WMSDs in the new revision of the list of occupational diseases in China.

Incidence and Risk Factors of the Upper-Limb Musculoskeletal Disorders Among Occupational Groups in Key Industries—China,2018–2021

What is already known about this topic?The burden of illness and economic losses due to upper-limb work-related musculoskeletal disorders(UL-WMSDs)is high;thus,they have become a major global public health problem.At present,the epidemiological characteristics of UL-WMSDs in China's occupational population are still unknown.What is added by this report?The incidence of UL-WMSDs among key occupational groups in China is 22.5%,with distinct occupational characteristics.What are the implications for public health practice?This study has primarily determined the occurrence and potential risk factors of UL-WMSDs in key industries in China and provided data support for recommending prevention and control of the occurrence of such diseases in key industries in China,and in facilitating the addition into the China’s List of Legal Occupational Diseases.

Two-dimensional Pt_(2)P_(3)monolayer:A promising bifunctional electrocatalyst with different active sites for hydrogen evolution and CO_(2)reduction

Green hydrogen production and CO_(2) fixation have been identified as the fundamental techniques for sustainable economy.The open challenge is to develop high performance catalysts for hydrogen evolution reaction(HER)and CO_(2) electroreduction(CO_(2)ER)to valuable chemicals.Under such context,this work reported computational efforts to design promising electrocatalyst for HER and CO_(2)ER based on the swarm-intelligence algorithm.Among the family of transition-metal phosphides(TMPs),Pt_(2)P_(3) monolayer has been identified as excellent bifunctional catalysts due to high stability,excellent conductivity and superior catalytic performance.Different from typical d-block catalysts,p-band center presented by P atoms within Pt_(2)P_(3) monolayer plays the essential role for its reactivity towards HER and CO_(2)ER,underlining the key value of p-electrons in advanced catalyst design and thus providing a promising strategy to further develop novel catalysts made of p-block elements for various energy applications.

A Study of the Truncated Square Pyramid Geometry for Enhancement of Super-hydrophobicity

Super-hydrophobic surfaces are quite common in nature,inspiring people to continually explore its water-repellence property and applications to our lives.It has been generally agreed that the property of super-hydrophobicity is mainly contributed by the microscale or nanoscale(or even smaller)architecture on the surface.Besides,there is an energy barrier between the Cassie-Baxter wetting state and the Wenzel wetting state.An optimized square post micro structure with truncated square pyramid geometry is introduced in this work to increase the energy barrier,enhancing the robustness of super-hydrophobicity.Theoretical analysis is conducted based on the wetting transition energy curves.Numerical simulation based on a phase-field lattice Boltzmann method is carried out to verify the theoretical analysis.The numerical simulation agrees well with the theoretical analysis,showing the positive significance of the proposed micro structure.Furthermore,another novel micro structure of rough surface is presented,which combines the advantages of truncated pyramid geometry and noncommunicating roughness elements.Theoretical analysis shows that the novel micro structure of rough surface can effectively hinder the Cassie-Baxter state to Wenzel state transition,furthefly enhancing the robustness of the surface hydrophobicity.

Phthalocyanine-supported single-atom catalysts as a promising bifunctional electrocatalyst for ORR/OER: A computational study

Developing excellent performance catalysts for the oxygen reduction reaction(ORR)and oxygen evolution re-action(OER)is fundamental for the commercialization of energy transduction and storage equipment.In our works,the potential of plenty of transition metals(TMs)anchored on phthalocyanine(TM-Pc)(TM=Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Mo,Ru,Rh,Pd,Ag,Re,Os,Ir,and Pt)as electrocatalysts for the ORR/OER was sys-tematically explored through synthetic density functional theory(DFT)computations.These TM-Pc candidates exhibited high electrochemical stability owing to the intense binding among the anchored TM and the Pc-based substrate.Interestingly,the free energy profiles showed that Ir-Pc can be performed as an outstanding bifunc-tional electrocatalyst for ORR/OER due to its ultralow overpotentials(𝜂ORR=0.46 V and𝜂OER=0.23 V),which can be reasonably explained by energetic and electronic descriptors.The present findings not only expand the database of single-atom catalysts(SACs),but also open the way for the reasonable design and development of advanced electrocatalysts for renewable energy technology.