The biofilm characteristics and enhanced performance of a marine microbial-electrolysis-cell-based biosensor under positive anodic potential

Microbial fuel cells have already been used as biosensors to monitor assimilable organic carbon(AOC).However,their signal production from AOC is known to be completely suppressed by dissoved oxygen(DO).In this study,two identical microbial electrolysis cell(MEC)based biosensors were inoculated with marine sediment and operated at two different anodic potentials,namely-300 mV and+250 mV relative to Ag/AgCl.The MEC biosensor operated under positive anodic potential conditions had electrochemically active microbial communities on the anode,including members of the Shewanellaceae,Pseudoalteromonadaceae,and Clostridiaceae families.However,the strictly anaerobic members of the Desulfuromonadaceae,Desulfobulbaceae and Desulfobacteraceae families were found only in the negative anodic potential MEC biosensor.The positive anodic potential MEC biosensor showed several other advantages as well,such as faster start-up,significantly higher maximum current production,fivefold improvement in the AOC detection limit,and tolerance of low dissolved oxygen,compared to those obtained from the negative anodic potential MEC biosensor.The developed positive anodic potential MEC biosensor can thus be used as a real-time and inexpensive detector of AOC concentrations in high saline and low DO seawater.

Modification of the CuO electronic structure for enhanced selective electrochemical CO_(2) reduction to ethylene

Electrochemical carbon dioxide reduction reaction(CO_(2)RR)can produce value-added hydrocarbons from renewable electricity,providing a sustainable and promising approach to meet dual-carbon targets and alleviate the energy crisis.However,it is still challenging to improve the selectivity and stability of the products,especially the C^(2+) products.Here we propose to modulate the electronic structure of copper oxide(CuO)through lattice strain construction by zinc(Zn)doping to improve the selectivity of the catalyst to ethylene.Combined performance and in situ characterization analyses show that the compressive strain generated within the CuO lattice and the electronic structure modulation by Zn doping enhances the adsorption of the key intermediate*CO,thereby increasing the intrinsic activity of CO_(2)RR and inhibiting the hydrogen precipitation reaction.Among the best catalysts had significantly improved ethylene selectivity of 60.5%and partial current density of 500 mA·cm^(–2),and the highest C^(2+) Faraday efficiency of 71.47%.This paper provides a simple idea to study the modulation of CO_(2)RR properties by heteroatom doped and lattice strain.

Experimental and computational analysis of the structure-activity relationship of ionic gel electrolytes based on bistrifluoromethanesulfonimide salts for supercapacitors

Ionic gel(IG)electrolytes are emerging as promising components for the development of next-generation supercapacitors(SCs),offering benefits in terms of safety,cost-effectiveness,and flexibility.The ionic conductivity,stability,and mechanical properties of the gel electrolyte are relevant factors to be considered and the key to improving the performance of the SC.However,the structure–activity relationship between the internal structure of IGs and their SC properties is not fully understood.In the current study,the intuitive and regular structure–activity relationship between the structure and properties of IGs was revealed via combining computational simulation and experiment.In terms of conductivity,the ionic liquid(IL)([EMIM][TFSI])in the IG has a high self-diffusion coefficient calculated by molecular dynamics simulation(MDS),which is conductive to transfer and then improves the conductivity.The radial distribution function of the MDS shows that the larger the g(r)between the particles in the polymer network,the stronger the interaction.For stability,IGs based on[EMIM][TFSI]and[EOMIM][TFSI]ILs have higher density functional theory calculated binding energy,which is reflected in the excellent thermal stability and excellent capacitor cycle stability.Based on the internal pore size distribution and stress-strain characterization of the gel network([ME3MePy][TFSI]and[BMIM][TFSI]as additives),the highly crosslinked aggregate network significantly reduces the internal mesoporous distribution and plays a leading role in improving the mechanical properties of the network.By using this strategy,it will be possible to design the ideal structure of the IG and achieve excellent performance.

Fe-doped SnO_(2) nanosheet for ambient electrocatalytic nitrogen reduction reaction

Ammonia plays a vital role in the development of modern agriculture and industry.Compared to the conventional Haber–Bosch ammonia synthesis in industry,electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising and environmental friendly strategy to synthesize ammonia.Here,inspired by biological nitrogenase,we designed iron doped tin oxide(Fe-doped SnO_(2))for nitrogen reduction.In this work,iron can optimize the interface electron transfer and improve the poor conductivity of the pure SnO_(2),meanwhile,the synergistic effect between iron and Sn ions improves the catalyst activity.In the electrocatalytic NRR test,Fe-doped SnO_(2) exhibits a NH_(3) yield of 28.45μg·h^(−1)·mgcat^(−1),which is 2.1 times that of pure SnO_(2),and Faradaic efficiency of 6.54%at−0.8 V vs.RHE in 0.1 M Na_(2)SO_(4).It also shows good stability during a 12-h long-term stability test.Density functional theory calculations show that doped Fe atoms in SnO_(2) enhance catalysis performance of some Sn sites by strengthening N–Sn interaction and lowering the energy barrier of the rate-limiting step of NRR.The transient photovoltage test reveals that electrons in the low-frequency region are the key to determining the electron transfer ability of Fe-doped SnO_(2).