Regeneration of copper catalysts mediated by molybdenum-based oxides

Cu catalysts,known for their unparalleled catalytic capabilities due to their unique electronic structure,have faced inherent challenges in maintaining long-term effectiveness under harsh hydrogenation conditions.Here,we demonstrate a molybdenum-mediated redispersion behavior of Cu under hightemperature oxidation conditions.The oxidized Cu nanoparticles with rich metal-support interfaces tend to dissolve into the MoO_(3)support upon heating to 600℃,which facilitates the subsequent regeneration in a reducing atmosphere.A similar redispersion phenomenon is observed for Cu nanoparticles supported on Zn O-modified MoO_(3).The modification of ZnO significantly improves the performance of the Cu catalyst for CO_(2)hydrogenation to methanol,with the high activity being well maintained after four repeated oxidation-reduction cycles.In situ spectroscopic and theoretical analyses suggest that the interaction involved in the formation of the copper molybdate-like compound is the driving force for the redispersion of Cu.This method is applicable to various Mo-based oxide supports,offering a practical strategy for the regeneration of sintered Cu particles in hydrogenation applications.

具有表面活性的聚合物在洗涤剂中的应用研究

考察了一种丙烯酸-聚醚改性丙烯酸酯共聚物HS-C的结构特征、聚合物性能(螯合性、抗沉积性)以及表面活性(表面张力、临界胶束浓度、润湿性、乳化性、起泡性和去污力)。并分别对比了HS-C与常用螯合剂、抗再沉积剂以及表面活性剂在不同方面的性能。结果表明,HS-C的螯合值为554.70 mg/g,其螯合性能优于EDTA·4Na及GLDA·4Na,但略低于未改性的丙烯酸盐聚合物PM;其抗炭黑沉积性能与市售抗再沉积剂SRP接近,而PM无抗炭黑沉积作用。在表面活性方面,HS-C的临界胶束浓度和平衡表面张力分别为0.005%和41.85 mN/m;其润湿性能和泡沫性能比LAS、AEO-9、AES相对差,但乳化能力比低分子表面活性剂更好;HS-C具有比LAS更加优越的去污性能,与LAS、AEO-9、AES复配时存在协同增效去污的作用。

Construction of bifunctional single-atom catalysts on the optimized β-Mo_(2)C surface for highly selective hydrogenation of CO_(2) into ethanol

Green and economical CO_(2)utilization is significant for CO_(2)emission reduction and energy development.Here,the 1D Mo_(2)C nanowires with dominant(101)crystal surfaces were modified by the deposition of atomic functional components Rh and K.While unmodifiedβMo_(2)C could only convert CO_(2)to methanol,the designed catalyst of K_(0.2)Rh_(0.2)/β-Mo_(2)C exhibited up to 72.1%of ethanol selectivity at 150℃.It was observed that the atomically dispersed Rh could form the bifunctional active centres with the active carrierβMo_(2)C with the synergistic effects to achieve highly specific controlled C–C coupling.By promoting the CO_(2)adsorption and activation,the introduction of an alkali metal(K)mainly regulated the balanced performance of the two active centres,which in turn improved the hydrogenation selectivity.Overall,the controlled modification ofβMo_(2)C provides a new design strategy for the highly efficient,lowtemperature hydrogenation of CO_(2)to ethanol with single-atom catalysts,which provides an excellent example for the rational design of the complex catalysts.

Rational design and precise manipulation of nano‐catalysts

Nano‐catalysis plays a vital role in the chemical transformations and significantly impacts the booming modern chemical industry.The rapid technological enhancements have resulted in serious energy and environmental issues,which are currently spurring the exploration of the novel nano‐catalysts in diverse fields.In order to develop the efficient nano‐catalysts,it is essential to understand their fundamental physicochemical properties,including the coordination structures of the active centers and substrate‐adsorbate interactions.Subsequently,the nano‐catalyst design with precise manipulation at the atomic level can be attained.In this account,we have summarized our extensive investigation of the factors impacting nano‐catalysis,along with the synthetic strategies developed to prepare the nano‐catalysts for applications in electrocatalysis,photocatalysis and thermocatalysis.Finally,a brief conclusion and future research directions on nano‐catalysis have also been presented.

Tuning the coordination environment of single-atom catalyst M-N-C towards selective hydrogenation of functionalized nitroarenes

Fine-tuning of the coordination environment of single-atom catalysts(SACs)is effective to optimize their catalytic performances,yet it remains challenging due to the vulnerability of SACs.Herein,we report a new approach to engineering the coordination environment of M-N-C(M=Fe,Co,and Ni)SACs by using glutamic acid as the N/C source and pyrolysis atmosphere as a regulator.Compared with that in N2,NH3 was able to promote the doping of N at 7<700℃yet etch the N-species at higher temperatures,by which the M-N coordination number(CN)and the electronic structure were delicately tuned.It was found that the electron density of Ni single atoms increased with the decrease of Ni-N CN.As a consequence,the capability of Ni-N-C to dissociate H2 was greatly enhanced and a higher catalytic activity in chemoselective hydrogenation of functionalized nitroarenes was achieved.Moreover,this modulation method could be applied to other transition metals including Fe and Co.In particular,the as-synthesized Co-N-C SAC afforded a turnover frequency of 152.3 h~1 with 99%selectivity to 3-vinylaniline in the hydrogenation of 3-nitrostyrene,which was the highest ever reported thus far and was at least one order of magnitude more active than state-of-the-art noble-metal-free M-N-C catalysts,demonstrating the great potential of engineering the coordination environment of SACs.

Synthesis of Subnanometer-Sized Gold Clusters by a Simple Milling- Mediated Solid Reduction Method

An effective solvent-free method based on a solid-reduction process was developed to fabricate ultrafine gold catalysts. By this method we revealed a strong size-dependent activity of Au species in which subnanometer-sized clusters exhibited the best activity in the hydrogenation of CO_2 to formate, with a turnover number of up to 9278 over 7 h at 90 ℃.

Erratum to:Tuning the coordination environment of single-atom catalyst M-N-C towards selective hydrogenation of functionalized nitroarenes

Erratum to Nano Research https://doi.org/10.1007/s 12274-021-3511-z The affiliation of the author“Jianzhong Yin”was unfortunately mistakenly marked.This error did not affect any of the content and conclusions from the published paper.