Vertical 3D Nanostructures Boost Efficient Hydrogen Production Coupled with Glycerol Oxidation Under Alkaline Conditions

Hydrogen production from electrolytic water is an important sustainable technology to realize renewable energy conversion and carbon neutrality.However,it is limited by the high overpotential of oxygen evolution reaction(OER)at the anode.To reduce the operating voltage of electrolyzer,herein thermodynamically favorable glycerol oxidation reaction(GOR)is proposed to replace the OER.Moreover,vertical Ni O flakes and NiMoNH nanopillars are developed to boost the reaction kinetics of anodic GOR and cathodic hydrogen evolution,respectively.Meanwhile,excluding the explosion risk of mixed H_2/O_(2),a cheap organic membrane is used to replace the expensive anion exchange membrane in the electrolyzer.Impressively,the electrolyzer delivers a remarkable reduction of operation voltage by 280 mV,and exhibits good long-term stability.This work provides a new paradigm of hydrogen production with low cost and good feasibility.

Atomic pair distribution function research on Li_2MnO_3 electrode structure evolution

The mechanism research of structure-related reactions on Li_2MnO_3 is important to enhance the electrochemical performance of lithium-manganese-rich layered oxides.Although there are some reports on the structure evolution of Li_2MnO_3 during cycling process,the employed research techniques are very limited,mainly in/ex-situ X-ray diffraction,X-ray absorption and transmission electron microscopy.Here,atomic pair distribution function,a method to study the local atomic arrangement on the basis of average spectroscopic information,is used for the first time to study the local structure evolution of Li_2MnO_3 during electrochemical charge/discharge cycles.The results clearly demonstrate that Mn^(3+)/Mn^(4+) redox couple is activated and Mn ions are reduced during discharging process.Some Mn ions in Mn layers can significantly migrate to Li layers and occupy the octahedral sites.As a result,a portion of inserted Li ions can occupy the face-shared tetrahedron sites,accompanied by the formation of local spinel-like structure.This work provides an important and suitable method based on the average spectroscopic information to investigate the local structure of electrode materials of lithium-ion batteries as well as other advanced battery systems.

Binary-ternary transition metal chalcogenides interlayer coupling in van der Waals type-II heterostructure for visible-infrared photodetector with efficient suppression dark currents

Ternary two-dimentional(2D)materials exhibit diverse physical properties depending on their composition,structure,and thickness.Through forming heterostructures with other binary materials that show similar structure,there can be numerous potential applications of these ternary 2D materials.In this work,we reported the structure of few-layer CrPS_(4)by X-ray diffraction,transmission electron microscope,and electron-density distribution calculation.We also demonstrated a new application of the CrPS_(4)/MoS_(2)heterobilayer:visible-infrared photodetectors with type-II staggered band alignment at room temperature.The response of the heterostructure to infrared light results from a strong interlayer coupling that reduces the energy interval in the junction area.Since the intrinsic bandgap of individual components determines wavelengths,the decrease in energy interval allows better detection of light that has a longer wavelength.We used photoluminescence(PL)spectroscopy,Kelvin probe force microscopy(KPFM)under illumination,and electrical transport measurements to verify the photoinduced charge separation between the CrPS_(4)/MoS_(2)heterostructures.At forward bias,the device functioned as a highly sensitive photodetector,as the wavelength-dependent photocurrent measurement achieved the observation of optical excitation from 532 to 1,450 nm wavelength.Moreover,the photocurrent caused by interlayer exciton reached around 1.2 nA at 1,095 nm wavelength.Our demonstration of the strong interlayer coupling in the CrPS_(4)/MoS_(2)heterostructure may further the understanding of the essential physics behind binary-ternary transition metal chalcogenides heterostructure and pave a way for their potential applications in visible-infrared devices.