Rational design of CO_(2)electroreduction cathode via in situ electrochemical phase transition

CO_(2)electroreduction reaction(CO_(2)RR),combined with solid oxide electrolysis cells(SOECs),is a feasible technology for the storage of renewable electric energy,while its development is limited by the catalytic activity and stability on cathodes.Here,a novel garnet oxide(Gd_(3)Fe_(5)O_(12))cathode is designed,where the garnet oxide is converted to perovskite oxide and iron via in situ electrochemical phase transition during CO_(2)electroreduction,resulting in high activity with Faradaic efficiency close to 100%and great stability over 1000 h galvanostatic test.A variety of experimental characterizations and density functional theory calculations indicate that in situ exsolved Fe clusters can effectively enhance the adsorption energies of intermediates and lowering the CO_(2)dissociation barriers.Microkinetic modelling confirms that CO_(2)RR goes through a dissociative adsorption mechanism and the electronic transfer for CO_(2)dissociation is the rate-determining step.

CORROSION FATIGUE BEHAVIOR OF STAINLESS STEEL 3RE60 IN 3.5% SODIUM CHLORIDE SOLUTION

The corrosion fatigue behavior of stainless steel 3RE60 in 3.5%NaCl solution was studied at different cyclic stress levels. The results showed that both intergranular corrosion cracking and transgranular corrosion cracking initiated at the bottom of pits. The corrosion fatigue behavior of 3RE60 may be related to complex electrochemical and mechanical coupling effects between the three phases (austenite, ferrite and martensite), where martensite and ferrite were anodic in the corrosion cell and could be prone to crack under certain conditions.

Electrochemical hydrogenation of mixed-phase TiO2 nanotube arrays enables remarkably enhanced photoelectrochemical water splitting performance

We first report that photoelectrochemical （PEC） performance of electrochemically hydrogenated TiO2 nanotube arrays （TNTAs） as high-efficiency photoanodes for solar water splitting could be well tuned by designing and adjusting the phase structure and composition of TNTAs. Among various TNTAs annealed at different temperature ranging from 300 to 700℃, well-crystallized single anatase （A） phase TNTAs-400 photoanode shows the best photoresponse properties and PEC performance due to the favor- able crystallinity, grain size and tubular structures. After electrochemical hydrogenation （EH）. anatase- rutile （A-R） mixed phase EH-TNTAs-600 photoanode exhibits the highest photoactivity and PEC perfor- mance for solar water splitting. Under simulated solar illumination, EH-TNTAs-600 achieves the best photoconversion efficiency of up to 1.52% and maximum H2 generation rate of 40.4 ~mol h i cm-2, our- stripping other EH-TNTAs photoanodes. Systematic studies reveal that the signigicantly enhanced PEC performance for A-R mixed phaes EH-TNTAs-600 photoanode could be attributed to the synergy of A-R mixed phases and intentionally introduced Ti3~ （oxygen vacancies） which enhances the photoactivity over both UV and visible-light regions, and boosts both charge separation and transfer efficiencies. These findings provide new insight and guidelines for the construction of highly efficient TiO2-based devices for the application of solar water splitting.

Structure and electrochemical properties of LaMgNi4-xCox(x=0-0.8)hydrogen storage electrode alloys

LaMgNi（4-x）Cox（x = 0-0.8） electrode alloys used for MH/Ni batteries were prepared by induction melting. The structures and electrochemical hydrogen storage properties of the alloys were investigated in detail.X-ray diffraction（XRD） and scanning electron microscopy（SEM） analysis show that LaMgNi4 phase and LaNi5 phase are obtained. The lattice parameters of the two phases increase first and then decrease with Co content increasing.The electrochemical properties of the alloy electrodes were measured by means of simulated battery tests. Results show that the addition of Co does not change the discharge voltage plateau of the alloy electrodes. However, the maximum discharge capacity increases from 319.9 mAh·g^-1（x = 0）to 347.5 mAh·g^-1（x = 0.4） and then decreases to331.7 mAh·g^-1（x = 0.8）. The effects of Co content on electrochemical kinetics of the alloy electrodes were also performed. The high rate dischargeability（HRD） first increases and then decreases with Co content increasing and reaches the maximum value（95.0 %） when x = 0.4. Test results of the electrochemical impedance spectra（EIS）,potentiodynamic polarization curves and constant potential step measurements of the alloy electrodes all demonstrate that when Co content is 0.4 at%, the alloy exhibits the best comprehensive electrochemical properties.