Unveiling the geometric site dependent activity of spinel Co_(3)O_(4)for electrocatalytic chlorine evolution reaction

Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catalytic contribution of geometric Co site in the electrocatalytic CER plays a pivotal role to precisely modulate electronic configuration of active Co sites to boost CER.Herein,combining density functional theory calculations and experiment results assisted with operando analysis,we found that the Co_(Oh) site acts as the main active site for CER in spinel Co_(3)O_(4),which shows better Cl^(-)adsorption and more moderate intermediate adsorption toward CER than CoTd site,and does not undergo redox transition under CER condition at applied potentials.Guided by above findings,the oxygen vacancies were further introduced into the Co_(3)O_(4) to precisely manipulate the electronic configuration of Co_(Oh) to boost Cl^(-)adsorption and optimize the reaction path of CER and thus to enhance the intrinsic CER activity significantly.Our work figures out the importance of geometric configuration dependent CER activity,shedding light on the rational design of advanced electrocatalysts from geometric configuration optimization at the atomic level.

Self-powered electrochemical system by combining Fenton reaction and active chlorine geheration for organic contaminant treatment

Environmental deterioration,especially water pollution,is widely dispersed and could affect the quality of people's life at large.Though the sewage treatment plants are constructed to meet the demands of cities,distributed treatment units are still in request for the supplementary of centralized purification beyond the range of plants.Electrochemical degradation can reduce organic pollution to some degree,but it has to be powered.Triboelectric nanogenerator(TENG)is a newly-invented technology for low-frequency mechanical energy harvesting.Here,by integrating a rotary TENG(R-TENG)as electric power source with an electrochemical cell containing a modified graphite felt cathode for hydrogen peroxide(H2O2)along with hydroxyl radical(·OH)generation by Fenton reaction and a platinum sheet anode for active chlorine generation,a self-powered electrochemical system(SPECS)was constructed.Under the driven of mechanical energy or wind flow,such SPECS can efficiently degrade dyes after power management in neutral condition without any O2 aeration.This work not only provides a guideline for optimizing self-powered electrochemical reaction,but also displays a strategy based on the conversion from distributed mechanical energy to chemical energy for environmental remediation.

Evaluation of CC2 as a Decontaminant in Various Hydrophilicand Lipophilic Formulations Against Sulphur Mustard

Objective To evaluate CC2 (N, N’-dichloro-bis [2, 4, 6-trichlorophenyl] urea) invarious hydrophilic and lipophilic formulations as a personnel decontaminant for sulphurmustard (SM). Methods Twenty percent of CC2 was prepared as a suspension or ointmentwith various chemical agents and its stability was evaluated by active chlorine assay. Theefficacy was evaluated in mice by recording the mortality after applying 29 LD50 of SM (LD50 =8.1 mg/kg dermally) and decontaminating it after 2 min with 200 mg of the formulation.Studies were also carried out with 10% and 20% CC2 in acacia and hydroxypropyl cellulose,and the suspensions were stored in polyethylene containers. The stability of the suspensionswas evaluated by active chlorine assay. The efficacy was evaluated by recording themortality after applying 29 LD50 of SM in mice and 12 LD50 of SM in rats (LD50 = 2.4 mg/kgdermally), and decontaminating it with the formulations. LD50 by different routes andprimary skin irritation test of CC2 were also carried out. Results CC2 reacted with peanutoil and neem oil, and was unstable in povidone iodine and Fuller’s earth. Good stability wasachieved with petroleum jelly, honey, polyvinyl pyrrolidone, calamine lotion, acacia andhydroxypropyl cellulose. Though CC2 was stable in lipophilic formulations, it did notprotect the animals. The hydrophilic formulations particularly acacia and hydroxypropylcellulose gave very good protection and was stable in the polyethylene containers for aperiod of 1 year. The efficacy of 20% CC2 was better than 10% CC2. The oral and dermalLD50 of CC2 was found to be above 5.0 g/kg. CC2 was also found to be nonirritant.Conclusion Twenty percent of CC2 in hydroxypropyl cellulose is better with respect tostability, efficacy and ease of decontamination. CC2 is also a safe chemical.