Cu-based materials for electrocatalytic CO_(2) to alcohols:Reaction mechanism,catalyst categories,and regulation strategies

Electrocatalytic CO_(2) reduction reaction(CO_(2)RR)technology,which enables carbon capture storage and resource utilization by reducing CO_(2) to valuable chemicals or fuels,has become a global research hotspot in recent decades.Among the many products of CO_(2)RR(carbon monoxide,acids,aldehydes and alcohols,olefins,etc.),alcohols(methanol,ethanol,propanol,etc.)have a higher market value and energy density,but it is also more difficult to produce.Copper is known to be effective in catalyzing CO_(2) to high valueadded alcohols,but with poor selectivity.The progress of Cu-based catalysts for the selective generation of alcohols,including copper oxides,bimetals,single atoms and composites is reviewed.Meanwhile,to improve Cu-based catalyst activity and modulate product selectivity,the modulation strategies are straighten out,including morphological regulation,crystalline surface,oxidation state,as well as elemental doping and defect engineering.Based on the research progress of electrocatalytic CO_(2) reduction for alcohol production on Cu-based materials,the reaction pathways and the key intermediates of the electrocatalytic CO_(2)RR to methanol,ethanol and propanol are summarized.Finally,the problems of traditional electrocatalytic CO_(2)RR are introduced,and the future applications of machine learning and theoretical calculations are prospected.An in-depth discussion and a comprehensive review of the reaction mechanism,catalyst types and regulation strategies were carried out with a view to promoting the development of electrocatalytic CO_(2)RR to alcohols.

Breaking the Fe_(3)O_(4)-wrapped copper microstructure to enhance copper-slag separation

The precipitation of Fe_(3)O_(4)particles and the accompanied formation of Fe_(3)O_(4)-wrapped copper structure are the main obstacles to copper recovery from the molten slag during the pyrometallurgical smelting of copper concentrates.Herein,the commercial powdery pyrite or anthracite is replaced with pyrite-anthracite pellets as the reductants to remove a large amount of Fe_(3)O_(4)particles in the molten slag,resulting in a deep fracture in the Fe_(3)O_(4)-wrapped copper microstructure and the full exposure of the copper matte cores.When 1wt%composite pellet is used as the reductant,the copper matte droplets are enlarged greatly from 25μm to a size observable by the naked eye,with the copper content being enriched remarkably from 1.2wt%to 4.5wt%.Density functional theory calculation results imply that the formation of the Fe_(3)O_(4)-wrapped copper structure is due to the preferential adhesion of Cu_(2)S on the Fe_(3)O_(4)particles.X-ray photoelectron spectroscopy,Fourier transform infrared spectrometer(FTIR),and Raman spectroscopy results all reveal that the high-efficiency conver-sion of Fe_(3)O_(4)to FeO can decrease the volume fraction of the solid phase and promote the depolymerization of silicate network structure.As a consequence,the settling of copper matte droplets is enhanced due to the lowered slag viscosity,contributing to the high efficiency of copper-slag separation for copper recovery.The results provide new insights into the enhanced in-situ enrichment of copper from mol-ten slag.

Identification for temperature model of accelerometer based on proximal SVR and particle swarm optimization algorithms

The impact of temperature on accelerometer will directly influence the precision of the inertial naviga- tion system （INS）. To eliminate the measurement error of accelerometer, this paper proposes a proximal support vector regression （PSVR） algorithm for generating a linear or nonlinear regression which requires the solution to single system of linear equations. PSVR is used to identify the static temperature model of the accelerometer. In order to improve the identifying performance, the kernel parameters and penalty factors of PSVR are optimized by the canonical particle swarm optimization （CPSO）. The experiments under different temperature conditions were conducted. The experimental results show that the proposed PSVR can correctly identify the static temperature model of quartz flexure accelerometer and is more efficient than those of the standard SVR and least square algorithm.

Self-supporting hierarchically micro/nano-porous Ni_(3)P-Co_(2)P-based film with high hydrophilicity for efficient hydrogen production

Designing efficient and stable non-precious metal HER(hydrogen evolution reaction)electrocatalysts with high large current density adaptability is significant for industrial application of hydrogen production by water electrolysis.Herein,a facile strategy was developed to construct a multi-phase Ni3 P-Co_(2)P-(Ni-Co)film with self-supporting hierarchically micro/nano-porous structure by using bubble template method electrodeposition of self-supporting micro-porous Ni Co P film,oxygen-free annealing for phase separation producing Ni_(3)P-Ni-Co_(2)P-Co structure,and acid etching for constructing surface nano-porous structure.The effective active sites for HER was significantly increased due to the hierarchically micro/nano-porous structure,which not only enlarged the surface roughness,but enhanced the bubble detachment by improving the hydrophilicity.Meanwhile,the HER electrolysis durability was improved benefiting from the Ni_(3)P-Co_(2)P phases with high corrosion resistance(especially in acid solution)and the self-supporting film structure without binder.Consequently,the Ni Co P-OA-AE film exhibited high HER catalytic performance,which delivered a current density of 10 m A cm^(-2)at a low overpotential of 42.9 and 39.7 m V in 1 M KOH and 0.5 M H_(2)SO_(4),respectively.It also possessed high long-term electrolysis durability,and the cell voltage of water electrolysis using self-supporting porous Ni Co P-OA-AE||Ir O_(2)-Ta_(2)O_(5) electrolyzer at 500 m A cm^(-2)for 250 h in 0.5 M H_(2)SO_(4 )is only 2.9 V.

Bifunctional hierarchical NiCoP@FeNi LDH nanosheet array electrocatalyst for industrial-scale high-current-density water splitting

Aiming to design and prepare non-noble metal electrocatalysts for hydrogen production at high current density(HCD),NiCoP@FeNi LDH hierarchical nanosheets were deposited on nickel foam progressively us-ing a hydrothermal-phosphorization-electrodeposition process.For hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),NiCoP@FeNi LDH/NF requires only 195 and 230 mV overpotentials to reach 1000 mA cm−2,respectively.For overall water splitting,only 1.70 V is required at 1000 mA cm−2.This is the largest value for non-noble metal-based electrocatalysts reported so far at HCD.The hierarchi-cal structure exhibits good electron transport capability and the porous-macroporous structure enhances the gas release rate,resulting in enhanced hydrogen production at HCD.Especially,the synergistic effect of NiCoP and FeNi LDH contributes to the adsorption-desorption equilibrium of intermediate radicals dur-ing the reaction process and ultimately enhances the catalytic activity.This work provides useful direction for industrial-scale hydrogen production applications at HCD.