Search

Electrochemical CO2 reduction reaction (CO2RR) offers a sustainable strategy for producing fuels and chemicals. However, it suffers from sluggish CO2 activation and slow water dissociation. In this work, we construct a (P−O)δ− modified In catalyst that exhibits high activity and selectivity in electrochemical CO2 reduction to formate. A combination of in situ characterizations and kinetic analyses indicate that (P−O)δ− has a strong interaction with K+(H2O)n, which effectively accelerates water dissociation to provide protons. In situ attenuated total reflectance surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS) measurements together with density functional theory (DFT) calculations disclose that (P−O)δ− modification leads to a higher valence state of In active site, thus promoting CO2 activation and HCOO* formation, while inhibiting competitive hydrogen evolution reaction (HER). As a result, the (P−O)δ− modified oxide‐derived In catalyst exhibits excellent formate selectivity across a broad potential window with a formate Faradaic efficiency as high as 92.1 % at a partial current density of ~200 mA cm−2 and a cathodic potential of −1.2 V vs. RHE in an alkaline electrolyte. [ABSTRACT FROM AUTHOR]

Electrochemical CO2 reduction reaction (CO2RR) provides a renewable approach to transform CO2 to produce chemicals and fuels. Unfortunately, it faces the challenges of sluggish CO2 activation and slow water dissociation. This study reports the modification of Bi‐based electrocatalyst by S, which leads to a remarkable enhancement in activity and selectivity during electrochemical CO2 reduction to formate. Based on comprehensive in situ examinations and kinetic evaluations, it is observed that the presence of S species over Bi catalyst can significantly enhance its interaction with K+(H2O)n, facilitating fast dissociation of water molecules to generate protons. Further in situ attenuated total reflectance surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS) and in situ Raman spectroscopy measurements reveal that S modification is able to decrease the oxidation state of Bi active site, which can effectively enhance CO2 activation and facilitate HCOO* intermediate formation while suppressing competing hydrogen evolution reaction. Consequently, the S‐modified Bi catalyst achieves impressive electrochemical CO2RR performance, reaching a formate Faradaic efficiency (FEformate) of 91.2% at a formate partial current density of ≈135 mA cm−2 and a potential of −0.8 V versus RHE in an alkaline electrolyte. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Electrocatalytic reduction of CO2 to fuels and chemicals possesses huge potential to alleviate current environmental crisis. Heteroatom doping in metal‐nitrogen‐carbon (M‐N‐C) single‐atom catalysts (SACs) has been found to be capable to promote the electrocatalytic CO2 reduction reaction (CO2RR). However, the origin of the enhanced activity is still elusive. Here, we report that sulfur‐doped cobalt‐nitrogen‐carbon single‐atom catalyst (Co1‐SNC) exhibits superior CO2RR performance compared to sulfur‐free counterpart (Co1‐NC). On the basis of in situ attenuated total reflectance surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS), kinetic isotope effect (KIE) and theoretical calculation, it is demonstrated that sulfur doping can promote water activation, elevate the d‐band center of Co active site, and reduce the free energy of *COOH intermediate formation. This work deepens the understanding of the CO2RR chemistry over heteroatom‐doped SACs for designing efficient CO2RR processes. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Electrocatalytic reduction of CO2 to fuels and chemicals possesses huge potential to alleviate current environmental crisis. Heteroatom doping in metal‐nitrogen‐carbon (M‐N‐C) single‐atom catalysts (SACs) has been found to be capable to promote the electrocatalytic CO2 reduction reaction (CO2RR). However, the origin of the enhanced activity is still elusive. Here, we report that sulfur‐doped cobalt‐nitrogen‐carbon single‐atom catalyst (Co1‐SNC) exhibits superior CO2RR performance compared to sulfur‐free counterpart (Co1‐NC). On the basis of in situ attenuated total reflectance surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS), kinetic isotope effect (KIE) and theoretical calculation, it is demonstrated that sulfur doping can promote water activation, elevate the d‐band center of Co active site, and reduce the free energy of *COOH intermediate formation. This work deepens the understanding of the CO2RR chemistry over heteroatom‐doped SACs for designing efficient CO2RR processes. [ABSTRACT FROM AUTHOR]

Single‐atom catalysts exhibit superior CO2‐to‐CO catalytic activity, but poor kinetics of proton‐coupled electron transfer (PCET) steps still limit the overall performance toward the industrial scale. Here, we constructed a Fe−P atom paired catalyst onto nitrogen doped graphitic layer (Fe1/PNG) to accelerate PCET step. Fe1/PNG delivers an industrial CO current of 1 A with FECO over 90 % at 2.5 V in a membrane‐electrode assembly, overperforming the CO current of Fe1/NG by more than 300 %. We also decrypted the synergistic effects of the P atom in the Fe−P atom pair using operando techniques and density functional theory, revealing that the P atom provides additional adsorption sites for accelerating water dissociation, boosting the hydrogenation of CO2, and enhancing the activity of CO2 reduction. This atom‐pair catalytic strategy can modulate multiple reactants and intermediates to break through the inherent limitations of single‐atom catalysts. [ABSTRACT FROM AUTHOR]

With the increase of thermal and mechanical load of engine,the higher standards were required for materials,and the more serious challenges had been taken for the design technology. Based on simulation results of several cylinder heads,which had been strengthened,a relatively optimal frame cylinder head was obtained. The load carrying structures,which were interdependent,were included by bolt holes,the fuel injector holes,stiffeners of the top ceiling and the fire face. The results of reliability tests about mechanical fatigue and thermal fatigue revealed the structure of the Al- alloyed cylinder head under peak pressure（ 20 MPa） was reasonable.

An orchard variable-rate sprayer applies the appropriate amount of plant protection products only where they are needed based on detection data from advanced sensors, a system that has attracted increasing attention. The latest developments in the detection unit, variable control unit, and signal-processing algorithm of the variable-rate sprayer are discussed. The detection of target position and volume is realized with an ultrasonic sensor, a laser scanning sensor, or other methods. The technology of real-time acquisition of foliage density, plant diseases and pests and their severity, as well as meteorological parameters needs further improvements. Among the three variable-flow-rate control units, pulse width modulation was the most widely used, followed by pressure-based, and variable concentration, which is preliminarily verified in the laboratory. The variable air supply control unit is tested both in the laboratory and in field experiments. The tree-row-volume model, the leaf-wall-area model, and the continuous application mode are widely used algorithms. Advanced research on a variable-rate sprayer is analyzed and future prospects are pointed out. A laser-based variable-rate intelligent sprayer equipped with pulse width modulation solenoid valves to tune spray outputs in real time based on target structures may have the potential to be successfully adopted by growers on a large scale in the foreseeable future. It will be a future research direction to develop an intelligent multi-sensor-fusion variable-rate sprayer based on target crop characteristics, plant diseases and pests and their severity, as well as meteorological conditions while achieving multi-variable control. [ABSTRACT FROM AUTHOR]