PdCu single atom alloys supported on alumina for the selective hydrogenation of furfural

Single-atom catalysts serve as a skilful control of precious metals on heterogenous catalysts where all active sites are accessible for catalytic reactions. Here we report the adoption of PdCu single-atom alloys supported on alumina for the selective hydrogenation of furfural. This is a special class of an atom efficient, single-site catalyst where trace concentrations of Pd atoms (0.0067 wt%) displace surface Cu sites on the host nanoparticle. Confirmed by EXAFS, the Pd atoms are entirely coordinated to Cu, with Pd-Cu bond lengths identical to that of a Cu-Cu bond. Selectively surface oxidised catalysts also confirm surface Pd atoms by EXAFS. These catalysts improve the conversion of furfural to furfuryl alcohol compared to monometallic catalysts, as they have the advantages of Cu (high selectivity but poor activity) and Pd catalysts (superior activity but unselective) without the drawbacks, making them the optimal catalysts for green/atom efficient catalysis

Synthesis of amine functionalized mesoporous silicas templated by castor oil for transesterification

Mesoporous silicas were synthesized via a surfactant-templated sol-gel route using castor oil as the templating agent under acidic medium. The resulting silicas were subsequently amine functionalized with 3-aminopropyltriethoxysilane (NH2-MTS), [3-(2-aminoethylamino)-propyl]trimethoxysilane (NN-MTS), and [3-(diethylamino)propyl]trimethoxysilane(DN-MTS) to introduce surface basicity. Surface physicochemical properties were characterized by field emission gun scanning electron microscopy (FEGSEM), nitrogen porosimetry, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and diffuse reflectance infrared fourier transform spectroscopy (DRIFTS). As-synthesised materials exhibit type IV adsorption-desorption isotherms characteristic of mesoporous structures. Clusters of spherical shaped materials were observed by FEGSEM, suggesting growth of silica occurs within colloidal dispersions. High-resolution N 1s XP spectra and DRIFT spectra confirmed the presence of amine groups in the organo-amine functionalised mesoporous silicas. The amine functionalised mesoporous silicas were active for the transesterification of tributyrin with methanol, with conversion found to increase from NH2-MTS< NN-MTS< DN-MTS

Delaminated CoAl‐Layered Double Hydroxide@TiO₂ Heterojunction Nanocomposites for Photocatalytic Reduction of CO₂

Photocatalytic reduction offers an attractive route for CO_{2} utilization as a chemical feedstock for solar fuels production but remains challenging due to the poor efficiency, instability, and/or toxicity of current catalyst systems. Delaminated CoAl‐layered double hydroxide nanosheets (LDH‐DS) combined with TiO_{2} nanotubes (NTs) or nanoparticles (NPs) are promising nanocomposite photocatalysts for CO_{2} reduction. Heterojunction formation between visible light absorbing delaminated CoAl nanosheets and UV light absorbing TiO_{2} nanotubes greatly enhances interfacial contact between both high aspect ratio components relative to their bulk counterparts. The resulting synergic interaction confers a significant improvement in photoinduced charge carrier separation, and concomitant aqueous phase CO_{2} photocatalytic reduction, in the absence of a sacrificial hole acceptor. CO productivity for a 3 wt% LDH‐DS@TiO2‐NT nanocomposite of 4.57 µmol g_{cat}^{-1} h^{-1} exhibits a tenfold and fivefold increase over that obtained for individual TiO2 NT and delaminated CoAl‐LDH components respectively and is double that obtained for 3 wt% bulk‐LDH@TiO_{2}-NT and 3 wt% LDH‐DS@TiO2‐NP catalysts. Synthesis of delaminated LDH and metal oxide nanocomposites represents a cost‐effective strategy for aqueous phase CO_{2} reduction

Unravelling mass transport in hierarchically porous catalysts

Hierarchical porous catalysts offer highly connected architectures for enhanced transport of bulky molecules and the sustainable manufacturing of bio-derived platform chemicals and fuels.</p