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The effective coupling of photoinduced alcohol oxidation and water reduction may economically produce hydrogen (H2) from water, which is of great significance in solving the current energy crisis. This study discloses that decatungstate (DT) and especially Ni2+ions-doped DTs are active for the photoreaction of benzyl alcohol with H2O, and under 48 h of violet light illumination, the best 1%Ni-DT yields ca. 86.1% benzoic acid and a 4.65 h–1H2generation efficiency (turnover frequency, TOF). Also, 1%Ni-DT is efficient for the photoredox coupling reaction of aliphatic and especially aromatic primary/secondary alcohols with water. A series of characterizations support that the doubled-reduced H2DT produced from the photoreaction plays a key role in water reduction to H2, which is accelerated by the doped Ni2+. In particular, it and the derived Ni3+may construct a Z-type catalyst for water overall splitting, thereby hoisting the acid yield and H2amount in the later stage of the photoreaction.

This paper discloses a simple and productive strategy for the preparation of biochar-based bifunctional catalysts. In this strategy, very cheap bamboo powder is thermally carbonized to yield P-containing porous biochars (PBCs) by the activation of concentrated phosphoric acid (H3PO4), and the latter can be transformed into the target catalysts vialoading Ru nanometer particles (NPs) on them (marked as Ru/PBCs). A series of characterizations and measurements support that PBCs have stable and rich micro-meso pores and small strong acidic protons (0.10–0.28 mmol·g-1) attributable to the grafted and/or skeleton phosphorus groups, as well as a strong affinity to ß-1,4-glycosidic bonds, thus exhibiting a good acid catalytic activity for the hydrolysis of cellulose to glucose. More importantly, they are excellent acidic supports for the loading of Ru NPs owing to high BET surface area, which can give the loaded Ru NPs uniform and narrow distribution (1–6 nm). The resulting bifunctional Ru/PBCs catalysts possess excellent hydrolytic hydrogenating activity for the one-pot cascade conversion of cellulose and the optimized conditions can achieve ca. 89% hexitol yield with 98% sorbitol selectivity under relatively mild conditions. This work provides a good example for the preparation of biomass-derived bifunctional catalysts and their applications in biorefinery.Ru-loaded P-containing porous biochar (Ru/PBC), as a robust bifunctional catalyst, is very active for the one-pot cascade conversion of cellulose in water under H2atmosphere, affording ca. 89% hexitol yield with 98% sorbitol selectivity under relatively mild conditions.

This paper discloses a simple and productive hybridizing engineering (HE) strategy for the 3d transition-metal-ion (Mn+= Fe3+, Fe2+, Co2+, Ni2+)-doped (nBu4N)4W10O32(Mn+-TBADT) compounds as highly efficient visible-light catalysts. Ultraviolet visible (UV–vis), Fourier transform infrared (FT-IR) and photoluminescence (PL) spectra, and cyclic voltammetry (CV) characterizations indicate that the synthetic quality, redox capacity, and visible light harvesting efficiency of TBADT, especially the separation efficiency of its photogenerated electron–hole pairs, are regulated by the metal ion dopants and gradually improved with a change of the dopant from Fe3+, Fe2+, and Co2+to Ni2+, along with a continuous and significant enhancement of its photocatalytic efficiency in the visible-light-triggered selective oxidation of ethylbenzene with dioxygens in acetonitrile. The best 0.5 mol % Ni2+-doped TBADT can achieve a ca. 55% conversion under optimal reaction conditions and also exhibits much higher photocatalytic activity for the photo-oxidation of toluene, cyclohexane, and benzyl alcohol compared to pure TBADT. This HE strategy showcases great potential in improving the photocatalysis performance of TBADT.

This paper reports a new strategy for the structural reconstruction of biomass carbon sulfonic acid (BCSA) to its solid superacid counterpart. In this approach, a cheap layered biomass carbon (BC) source is chemically exfoliated by cetyltrimethyl ammonium bromide and then converted to silica-isolated carbon nanosheets (CNSs) by a series of conversion steps. The state of the silica-isolated CNSs and the stacking density of their nanoparticles are regulated by the dehydration temperature. Only the highly isolated and non-crosslinked CNSs with loose particle stacking structures obtained upon dehydration at 250 °C can be turned into superacid sites (with stronger acidity than that of 100% H2SO4) after sulfonation. This is accompanied by the creation of abundant hierarchical slit pores with high external surface area, mainly driven by the strong hydrogen bonding interactions between the introduced sulfonic acid groups. In typical acid-catalyzed esterification, etherification, and hydrolysis reactions, the newly formed superacid exhibits superior catalytic activity and stability compared to those of common BCSA and commercial Amberlyst-15 catalysts, owing to its good structural stability, highly exposed stable superacidic sites, and abundance of mesoporous/macroporous channels with excellent mass transfer rate. This groundbreaking work not only provides a novel strategy for fabricating bio-based solid superacids, but also overcomes the drawbacks of BCSA, i.e., unsatisfactory structural stability, acidity, and porosity.

The rich and stable interlayer porous biomass carbon sulfonic acids (SBCSAs) pillared by silica were prepared conveniently using bamboo powder and water glass as main raw materials and investigated by a series of characterization techniques. Additionally, the acid catalysis performances of SBCSAs were evaluated using the hydrolysis of sucrose, the esterification of oleic acid with methanol and the alkylation of toluene with benzyl chloride. The results showed that 0.05–0.025 M acidic silica sols could be efficiently and uniformly intercalated into the interlayers between bamboo carbon (BC) nanosheets, yielding the silica-pillared BC materials (SBCs) with rich interlayer slit-like pores after dehydration at 350 °C. Moreover, the porosity of SBCs could be very well kept after further sulfonation with concentrated sulfuric acid. The newly constructed SBCSA materials exhibited higher catalysis efficiency and better reusability for the above acid-catalyzed reactions than the non-pillared BCSA and commercial Amberlyst-15, which should be due to the overall improvements relating to their structure, porosity and acidity, as supported by BET, TGA, STEM-EDS and solid-state 31P MAS NMR spectra of adsorbed TMPO. This work opens up a new voyage for the fabrication of porous bio-based solid acids with good catalysis properties and extensive application prospect.This paper first discloses a preparation method for the silica-pillared biomass carbon sulfonic acids (SBCSAs) with stable interlayer slit-like pores and obviously improved activity and stability for the hydrolysis of sucrose and the alkylation of toluene with benzyl chloride.

Sulfamic acid functionalized PVC-coated nano-silica (NS) catalyst (NS@PVC-EDA-SO3H) was prepared viamulti-step treatment processes and characterized by FT-IR, N2adsorption-desorption, TGA/DTG, XRD, TEM, STEM-EDS, as well as acid-base back-titration. The hydroxyalkylation of phenol with formaldehyde to bisphenol F was employed to evaluate in detail its acid catalysis performances. The results indicated that the newly constructed NS@PVC-EDA-SO3H possessed richer short mesoporous to macroporous channels and highly exposed sulfamic acids and could exhibit excellent hydroxyalkylation activity and reusability owing to fast mass transfer and reaction rates for the conversion of substrates, as well as excellent structural and chemical stabilities. This new solid acid was obviously superior to the conventional homogeneous concentrated sulfuric acid and heterogeneous sulfonated resin catalysts in catalytic activity and reusability, which could achieve a remarkable formaldehyde conversion (99.9%) and selectivity of bisphenol F (94.5%) under optimal hydroxyalkylation conditions. Furthermore, it could also be recovered easily and used repeatedly at least nine times without an obvious decrease in activity.NS@PVC-EDA-SO3H catalysts with richer short mesoporous to macroporous channels and highly exposed sulfamic acids exhibit excellent hydroxyalkylation activity owing to their fast mass transfer and reaction rates for the conversion of substrates. Furthermore, it could also be recovered easily and used repeatedly at least nine times without an obvious decrease in activity.

This paper reports three bis(8-quinolinolato) oxovanadium(iv) complexes that are active for visible light-induced cyclohexane oxygenation under O2(1 atm) in acetonitrile with HCl participation, achieving greater than 18% conversion and 86% selectivity for KA oil (cyclohexanone and cyclohexanol), along with a small amount of chlorinated product. Notably, these VIVOQ2complexes are not only basically comparable to VIVO(acac)2and some typical VV-compounds in photocatalytic activity but are also more selective for KA oil. Spectral characterizations (XPS, FT-IR and UV-vis) and DFT calculations support that VIVOQ2complexes can be co-activated by HCl and O2to form the VVO(OH)-containing photoactive (PA) species with one pendant ligand's phenoxyl radical and an axially coordinated chlorine, which are responsible for the present photocatalytic oxidation. Noteworthily, increasing the Cl-substituents of VIVOQ2complexes and especially the amount of water in the reaction system obviously decelerated the generation of such PA species, which significantly improved the selectivity for KA oil.

Carbon-coated CdS (CdS@C) nanoparticles were conveniently prepared by a one-step hydrothermal carbonization method at temperature as low as 130 °C, in which cadmium acetate and glucose were used as the cadmium and carbon sources, respectively, and thiourea was used as the sulfur source and catalyst for the hydrothermal carbonization of glucose. The prepared CdS@C particles possess a smaller size, better dispersion, and more uniform distribution than pure CdS particles prepared under the same conditions. Furthermore, the hydrothermal carbonization of glucose easily induces the prior formation of metastable cubic CdS crystals. In addition, the carbonaceous species coated on the surface of CdS expands the range of absorption light and slightly decreases the band gap of CdS, as well as reduces the recombination of the photogenerated electron-hole pairs of CdS and its photo-oxidative corrosion, which can improve the photocatalytic activity and stability of CdS for the photo-oxidative degradation of methyl orange in aqueous solution under visible light irradiation.

This paper describes an electrochemical coupling epoxidation of cyclohexene by molecular oxygen (O2) under mild reaction conditions. Herein, the electroreduction of O2to hydrogen peroxide (H2O2) efficiently proceeds in a relatively environmentally friendly acetone/water medium containing electrolytes at 25–30 °C on a self-assembled H type of electrolysis cell with tree electrodes system, providing ca. 44.3 mM concentration of H2O2under the optimal electrolysis conditions. The epoxidation of cyclohexene with in situ generated H2O2simultaneously occurs upon catalysis by metal complexes, giving ca. 19.8 % of cyclohexene conversion with 78 % of epoxidative selectivity over the best catalyst 5-Cl-7-I-8-quinolinolato manganese(III) complex (Q3MnIII(e)). The present electrochemical coupling epoxidation result is nearly equivalent to the epoxidation of cyclohexene with adscititious H2O2catalyzed by the Q3MnIII(e).

A simple 5-chloro-7-iodo-8-quinolinolato-manganese(III) complex with the feature of pH-regulated molecular switches was conveniently synthesized and found to be a novel and highly efficient catalyst for the epoxidation of olefins with aqueous hydrogen peroxide in water-acetone media containing ammonium acetate and acetic acid as additives. This should be due to its special hexadentate binding structure that could be easily converted to the corresponding pentadentate form with a pendant hydroxy group viathe opening of an axial MnO bond in the reaction media, as supported by in situcyclic voltammetry and UV-vis spectra characterization.

Transition metals copper and titanium substituted mesoporous silicas (Cu-HMS and Ti-HMS) were synthesized at ambient temperature by using dodecylamine (DDA) surfactant as templating agent. XRD measurements prove that incorporating titanium and especially copper into the mesostructures causes the d100peaks of mesoporous silicas to become shifted to lower angles, indicating progressive expansion of the lattice d-spacings upon heteroatoms Ti and especially Cu incorporating. FT-IR measurements indicate that the calcined Cu-HMS and Ti-HMS samples all exhibit a weaker absorption band near 960 cm-1which may be rather a fingerprint of the heteroatom on the matrix of [SiO4] units whatever its crystallization state. Cu-HMS possesses relatively high catalytic activity for the hydroxylation of phenol with 30% aq. H2O2in aqueous solution (about 36% phenol conversion and more than 95% selectivity for dihydroxybenzene isomers), but Ti-HMS has no catalytic activity under the same reaction conditions. The product distribution obtained from Cu-HMS is completely different from that of the microporous titanium silicalite zeolites (TS zeolites). This is attributed to the porous structural differences between Cu-HMS and TS zeolites. The catalytic activity of the Cu-HMS is strongly dependent on the nature of the solvent; the Cu-HMS does not have any catalytic activity in the presence of organic solvents such as methanol or acetone instead of water. A reusing test of the recovered Cu-HMS indicates that the recovered catalyst suffers almost loss of activity and must be regenerated by calcination in air at 873 K in order to recover its activity.

The effects of various Lewis acids and reaction temperature on the regioselectivity of the Diels–Alder reaction of myrcene (7-methyl-3-methene-1,6-octadiene) with acrolein or methyl acrylate have been studied. The high regioselective `para' adducts were obtained when acrolein and methyl acrylate were used as dienophiles in the presence of ZnCl2and AlCl3catalyst, respectively. UV, 1HNMRand IR spectroscopic methods, were first used to investigate the interactions between acrolein and ZnCl2or methyl acrylate and AlCl3. The absorbance of the dienophile decreases and the maximum peak of the dienophile shifts to longer wave region in the UV spectra. All the protons' chemical shifts of the dienophile moves to downfield in the 1HNMRspectra. The CO stretching vibration of the dienophile shifts to a lower wave number region in the IR spectra. It is attributed to the coordination of acrolein with ZnCl2and of methyl acrylate with AlCl3. The dienophile activated by Lewis acid catalyst is advantageous for improving the `para/meta' regioselectivity and enhancing the reaction rate.

Titanium and B co-substituted silicate-2 zeolites were characterized using XRD, FT-IR and NH3-TPD, and the TBS-2′s bifunctional catalytic properties as oxidative and acidic catalysts were investigated using the epoxidation of styrene and rearrangement of styrene oxide.

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