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[Display omitted] • ZIF-8 derived ZnO@NC can anchor Ru nanoparticles to create Ru-O-Zn interface. • Ru/ZnO@NC achieved complete conversion and 99.2% GVL yield in LA hydrogenation. • Ru/ZnO@NC achieved excellent reaction activity with a TOF of 6032 h−1 at 40 °C. • Reaction mechanism of LA hydrogenation to GVL has been revealed by DFT calculation. • Ru-O-Zn interface can remarkably decline activation energy of rate-determining step. Highly efficient synthesis of valuable γ-valerolactone (GVL) by levulinic acid (LA) hydrogenation is of interest for biomass refinery, but it suffers from great challenge to design highly active Ru-based catalyst at low temperature. ZIF-8 derived ZnO@NC nanocomposite can firmly anchor Ru nanoparticles to create strong Ru-ZnO interfacial structure, as revealed by characterization techniques and DFT calculations. By optimizing Ru content and ZnO particle size, Ru/ZnO@NC achieved excellent reaction activity with a turnover frequency (TOF) of 6032 h−1 at low temperature of 40 °C, which is never reported before. After etching the accessible ZnO, the TOF value was significantly declined to 125 h−1 on Ru/ZnO@NC-HF owing to the lack of effective Ru-ZnO interface. DFT calculation results demonstrate that the Ru-ZnO interfacial structure can facilitate the activation of intermediate CH 3 CHOCH 2 CH 2 COOH* and remarkably decline the activation energy barrier of rate-determining step (CH 3 CHOCH 2 CH 2 COOH + H = HPA) from 1.28 eV to 0.82 eV, thus leading to excellent activity of LA hydrogenation at low temperature. [ABSTRACT FROM AUTHOR]

• Rod, cube and octahedral CeO 2 exposed (1 1 0), (1 0 0) and (1 1 1) facets in Ru/CeO 2. • Ru/CeO 2 -rod with exposed (1 1 0) facet achieved 99.4% GVL yield in EL hydrogenation. • DFT calculation elucidates reaction mechanism of EL hydrogenation to GVL on Ru/CeO 2. • The concentration of oxygen vacancy is linearly proportional to GVL production rate. • Surface CeO 2 structure and concentration of oxygen vacancy determine facet effect. Three Ru/CeO 2 catalysts with different CeO 2 morphology (nanorod, nanocube and nano-octahedra) mainly exposed (1 1 0) + (1 0 0), (1 0 0) and (1 1 1) facets for hydrogenation of biomass-derived ethyl levulinate (EL) to valuable γ-valerolactone (GVL). Ru/CeO 2 -rod with exposed (1 1 0) crystal plane obtained the highest GVL yield (99.4%) and best productivity (13140 h−1). The surface facets of CeO 2 supports not only affect the chemical states of Ru species but also tune the concentration of oxygen vacancy in Ru-CeO 2 interface. The concentration of oxygen vacancy shows a linear relationship with GVL production rate. DFT calculations indicate that the lactonization of CH 3 CHOCH 2 CH 2 CO* to produce GVL is the rate-determining step in EL hydrogenation, and Ru 10 /CeO 2 (1 1 0) with more oxygen vacancy has low activation energy barrier, compared to Ru 10 /CeO 2 (1 0 0) and Ru 10 /CeO 2 (1 1 1). [ABSTRACT FROM AUTHOR]

The effect of pH, contact time, temperature, ionic strength and initial U(VI) concentration on U(VI) sorption onto K-feldspar was investigated using batch techniques. The sorption kinetics was evaluated and the activation energy was obtained based on the rate constants at different temperature. Graphical correlations of sorption isotherm models have been evaluated and applied for U(VI) uptake by K-feldspar. Various thermodynamic parameters, such as, Gibb's free energy, entropy and enthalpy of the on-going sorption process have been calculated and the possible sorption mechanism of U(VI) was deduced. The results are expected to help better understand the migration of uranium in the host materials of granite. [ABSTRACT FROM AUTHOR]

• CoNi alloy encapsulated in N-doped thin graphene shell was synthesized from MOF. • One-pot cellulose conversion to γ-valerolactone using formic acid as hydrogen donor. • γ-Valerolactone yield reached as high as 55.9 % over AgPW/CoNi@NG. • Reaction mechanism of formic acid as hydrogen donor was revealed over CoNi@NG400. One-step efficient conversion of cellulose into value-added γ-valerolactone (GVL) is of great interest because it not only integrates complex tandem reactions in one-step, but also does not need additional hydrogen sources. To achieve this goal, it is crucial to fabricate high-performance catalyst that can accelerate both hydrolysis of cellulose and further transformation of generated stoichiometric levulinic acid (LA) and formic acid (FA) into GVL. CoNi nanoparticles encapsulated in N-doped thin graphene shell gave GVL yield as high as 55.9 % at 200 °C combined with Ag+-exchanged heteropolyacid (AgPW). This composite catalyst is highly resistant to the corrosion of LA and FA, and hence shows high catalytic stability. LA-adsorption FTIR spectra and DFT calculations indicate that LA and FA can penetrate through shell graphene layers into core CoNi sites via cracks. Compared to H 2 , FA can much more rapidly reduce LA because of its low dissociation energy barrier and high dissociation rate. [ABSTRACT FROM AUTHOR]