Abstract 5‐Hydroxymethylfurfural (HMF) can be oxidized to 2,5‐furandicarboxylic acid (FDCA) for the production of biorenewable plastics to replace fossil resourced polyethylene terephthalate (PET). Development of a highly efficient electrocatalyst using renewable electricity as energy input is highly desired. In this work, Ru cluster‐embedded Ni(OH) 2 nanosheets [Ru/Ni(OH) 2 ] were synthesized and exploited as electrochemical catalysts for the conversion of HMF to FDCA. Ru/Ni(OH) 2 exhibited significantly improved current density (40 mA cm −2 at 1.41 V vs. reversible hydrogen electrode) of over 7.7 times in comparison with Ni(OH) 2 , and nearly 100 % conversion degree for HMF and 98.5 % selectivity towards FDCA were obtained. Operando Raman experiments revealed the catalysis was facilitated by the interconversion between Ni 3+ and Ni 2+ . Density functional theory calculations further revealed the effect of Ru clusters of Ni(OH) 2 , thereby promoting HMF adsorption capacity on Ni sites to boost HMF oxidation activity. This work provides a novel strategy using Ru clusters to modify earth abundant Ni based catalyst for HMF oxidation to obtain high‐value biomass‐derived products.
Abstract Pd catalyzed selective hydrogenation of acetylene shows remarkable electronic effects. In this work, a strategy is proposed to tailor the electronic properties of Pd nanoparticles by nitrogen doping of carbon nanotubes (CNT) support toward the improved reaction kinetics. While excluding the Pd size effects, the intrinsic promotional effects of the nitrogen doping are demonstrated, which are mainly due to the increased Pd electron density resultant from the presence of more graphitic nitrogen species based on X‐ray photoelectron spectroscopy measurements and density functional theory (DFT) calculations. Kinetics analysis and C 2 H 2 /C 2 H 4 ‐temperature‐programmed desorption (TPD) measurements reveal that the electron‐rich Pd catalyst with the moderately weakened adsorption strength can give rise to the decreased activation energy and thus the simultaneously enhanced activity, selectivity, and stability. The aspects demonstrated here could guide the rational design and optimization of Pd catalysts for the selective hydrogenation of acetylene.
All-solid-state lithium-ion batteries (SSLIBs) are promising candidates to meet the requirement of electric vehicles due to the intrinsic safety characteristics and high theoretical energy density. A stable cathodic interface is critical for maximizing the performance of SSLIBs. In this study, operando X-ray absorption near-edge spectroscopy (XANES) combined with transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) is employed to investigate the interfacial behavior between the Ni-rich layered cathodes and sulfide solid-state electrolyte. The study demonstrates a metastable intermediate state of sulfide electrolyte at high voltage and parasitic reactions with cathodes during the charge/discharge process, which leads to the surface structural reconstruction of Ni-rich cathodes. Constructing a uniform interlayer by atomic layer deposition (ALD) is also employed in this study to further investigate the cathodic interface stability. These results provide new insight into the cathodic interface reaction mechanism and highlight the importance of advanced operando characterizations for SSLIBs.
A binder-free porous film of molybdenum carbide is synthesized by a facile approach, and exhibits superb performance in the alkaline hydrogen evolution reaction, producing a current density of 10 mA cm−2at an overpotential of 47 mV.
Computationally derived volcano curve has become the gold standard in catalysis, whose practical application usually relies on empirical interpretations of composition or size effects by the identical active site assumption. Here, we present a proof-of-concept study on disclosing both the support- and adsorbate-induced restructuring of Pt-Co bimetallic catalysts, and the related interplays among different interfacial sites to propose the synergy-dependent volcano curves. Multiple characterizations, isotopic kinetic investigations, and multiscale simulations unravel that the progressive incorporation of Co into Pt catalysts, driven by strong Pt-C bonding (metal-support interfaces) and Co-O bonding (metal-adsorbate interfaces), initiates the formation of Pt-rich alloys accompanied by isolated Co species, then Co segregation to epitaxial CoOx overlayers and adjacent Co3O4 clusters, and ultimately structural collapse into amorphous alloys. Accordingly, three distinct synergies, involving lattice oxygen redox from Pt-Co alloy/Co3O4 clusters, dual-active sites engineering via Pt-rich alloy/CoOx overlayer, and electron coupling within exposed alloy, are identified and quantified for CO oxidation (gas-phase), ammonia borane hydrolysis (liquid-phase), and hydrogen evolution reaction (electrocatalysis), respectively. The resultant synergy-dependent volcano curves represent an advancement over traditional composition-/size-dependent ones, serving as a bridge between theoretical models and experimental observations in bimetallic catalysis. Volcano curves have become the gold standard in catalyst design. Here, the authors propose synergy-dependent volcano curves by disclosing both support- and adsorbate-induced catalyst restructuring, ideally bridging the gap between theoretical models and experimental observations.
Abstract Pd catalysts are widely used in alkynol semi-hydrogenation. However, due to the existence of scaling relationships of adsorption energies between the key adsorbed species, the increase in conversion is frequently accompanied by side reactions, thereby reducing the selectivity to alkenols. We report that the simultaneous increase in alkenol selectivity and alkynol conversion is achieved by manipulating interstitial atoms including B, P, C, S and N in Pd catalysts. A negative linear relationship is observed between the activation entropies of 2-methyl-3-butyn-2-ol and 2-methyl-3-buten-2-ol which is highly related to the filling of d -orbital of Pd catalysts by the modification of p -block elements. A catalyst co-modified by B and C atoms has the maximum d charge of Pd that achieves a 17-fold increase in the turn-over frequency values compared to the Lindlar catalysts in the semi-hydrogenation of 2-methyl-3-butyn-2-ol. When the conversion is close to 100%, the selectivity can be as high as 95%.
Mine water disaster is one of the main natural disasters in underground mining operations, and seriously threatens the safety of mine production and personnel’s life, affecting mine safety and sustainable development. The research on the prevention and control of the disaster of water inrush in fractured rock mass has become a major international frontier issue in the field of underground engineering, and it is also a major national demand. The key to effectively preventing and controlling disasters is to reveal the mechanisms of disasters. Taking the Huize lead–zinc mine as an example, this paper deeply studies the application method of the transient electromagnetic method (TEM) in advance water detection in shaft and roadway development and field test results. In view of the complicated hydrogeological conditions of the mine and the serious threat of water damage, this paper puts forward a kind of advanced water detection technology for the Huize lead–zinc mine based on the mine transient electromagnetic method. The technology uses the principle of electromagnetic induction to detect the water-bearing structure ahead by placing the transmitting and receiving coils in the shaft. In the field test, the multi-turn small wire frame device is used to detect the direction of the roof, bedding and floor of the roadway head on. In roadway excavation, if the site meets the detection requirements, the abnormal low-resistance area in the test area can be exposed by drilling first. The degree of structural development and the peak value of water gushing in the target area have been mastered. Then, it is determined whether it is necessary to increase borehole exploration in other relatively high-resistance low-risk areas. The experimental results show that the mine transient electromagnetic method can accurately identify the low-resistance water in front, and provide reliable technical support for mine water disaster prevention. The research in this paper not only enriches the application field of the mine transient electromagnetic method, but also provides a useful reference for mine water damage prevention under similar conditions.
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