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Here, we demonstrate the selective cellobiose (building block of cellulose) photoreforming for gluconic acid and syngas co-production in acidic conditions by rationally designing a bifunctional polymeric carbon nitride (CN) with potassium/sulfur co-dopant. This heteroatomic doped CN photocatalyst possesses enhanced visible light absorption, higher charge separation efficiency than pristine CN. Under acidic conditions, cellobiose is not only more efficiently hydrolyzed into glucose but also promotes the syngas and gluconic acid production. Density functional theory (DFT) calculations reveal the favorable generation of •O 2 − during the photocatalytic reaction, which is essential for gluconic acid production. Consequently, the fine-designed photocatalyst presents excellent cellobiose conversion (>80%) and gluconic acid selectivity (>70%) together with the co-production of syngas (∼56 μmol g−1 h−1) under light illumination. The current work demonstrates the feasibility of biomass photoreforming with value-added chemicals and syngas co-production under mild condition. [Display omitted] • Bifunctional CN with K, S co-doping is synthesized via a facile calcination process. • Acidic cellobiose photoreforming to simultaneously obtain gluconic acid and syngas. • Cellobiose conversion (>80%) and gluconic acid selectivity (>70%) can be achieved. • Favorable generation of •O 2 − proved by DFT is essential for gluconic acid production. [ABSTRACT FROM AUTHOR]

• Three phosphate ester-based MOFs (UiO-66-(OPO 3) X) containing different amounts and spatial positions were prepared. • UiO-66-(OPO 3) X can efficiently remove Pb2+ from aqueous solution. • Even at pH = 2 and pH = 3, UiO-66-(OPO 3) X maintains a high removal efficiency of Pb2+. • UiO-66-(OPO 3) X has excellent selectivity and anti-interference ability for Pb2+. • The adsorption mechanism was investigated in detail by experiment combined with DFT. Metal-organic framework (MOF) materials have emerged as promising candidates for treating heavy metal wastewater because of their controllable pore size, high specific surface area, and abundant active sites. Nevertheless, the currently reported MOFs usually require near-neutral environments (pH = 5–6) to achieve efficient removal of Pb2+ and cannot be applied to acidic environments (pH = 2–3). In this work, the structurally stabilized zirconium-based MOF UiO-66 was chosen as the object of study. Three phosphate ester-based MOFs (UiO-66-(OPO 3) X) containing different amounts and spatial positions were designed and prepared by simple chemical modification and used to remove Pb2+. Adsorption experiments showed that they could reach adsorption equilibrium in 30 min with excellent adsorption rate. Owing to the unique ionization ability of the phosphate ester group, UiO-66-(OPO3) X maintains a high removal efficiency of Pb2+ even at pH = 2 and pH = 3. In addition, selectivity and competition experiments demonstrated that UiO-66-(OPO 3) X possessed excellent selectivity and anticompetitive ability towards Pb2+.The excellent regeneration performance demonstrates their value for practical application. Moreover, the adsorption mechanism was investigated in detail by experiment combined with density functional theory (DFT). [ABSTRACT FROM AUTHOR]

This work synthesizes Ni 2 P/ZCS composites to achieve spatial separation of photogenerated carriers, while systematically investigating the bifunctional properties and mechanisms of cellulose photoreforming. [Display omitted] • Preparation of Ni 2 P/ZCS to achieve space charge separation of photogenerated carriers. • Schottky junction in interface effectively improves catalyst photogenerated carrier separation and photostability. • Demonstrates excellent bifunctional catalytic performance for Ni 2 P/ZCS. • Ni 2 P/ZCS composites photoreforming cellulose mechanism is proposed for the first time. The Biomass photoreforming is emerging as an alternative and promising technology to simultaneously produce value-added chemicals and solar fuels. However, photoreforming of the biomass macromolecular remains a great challenge due to the lack of bifunctional photocatalyst and insight of detailed mechanism. Herein, we design the Ni 2 P onto the two-dimension Zn 0.3 Cd 0.7 S (Ni 2 P/ZCS) as the electron migration layer to realize the spatial separation of photogenerated carrier, which facilitates the depth investigation on the redox reaction. As a result, the Ni 2 P/ZCS exhibited dually catalytic performance (9.16 mmol g−1h−1 of H 2 generation along with 1.48 mmol g−1h−1 of lactic acid production) from cellulose photoreforming. Systematic experiments and density functional theory (DFT) were performed to reveal the bifunctionality and detailed mechanism. This work demonstrates a well concept on biomass photoreforming with the rational design of bifunctional photocatalysts. [ABSTRACT FROM AUTHOR]

A phenanthroline[9,10-d] imidazole-based fluorescent sensor was synthesized for Hg2+, accompanied by change of fluorescence from null to blue. [Display omitted] • A novel phenimidazole fluorescence sensor compound 1 was developed. • The sensor compound 1 exhibited fluorescent response to Hg2+. • Low cost, high sensitivity, superior selectivity, and low detection limit for Hg2+. • The sensor compound 1 had advantages in detecting Hg2+ in practical applications. Herein, a phenanthro[9,10-d] imidazole Schiff based "turn-on" fluorescence sensor (compound 1) was synthesized by 4-hydroxy-3-nitrobenzaldehyde and 9,10-phenanthrenequinone. In DMF/PBS buffer solution (1:4, v/v, pH 7.4), compound 1 responsed to Hg2+ with high sensitivity (detection limit was 45.76 nM) and rapid response (completed within 5 s), accompanied by the fluorescence change from null to blue. The binding ratio of compound 1 to Hg2+ was 1:1, and the binding constant was 2.933 × 106 M−1. Through detailed analysis of 1H–1H COSY and 1H–13C HSQC spectra, we proposed the possible fluorescence emission mechanism of compound 1 and Hg2+, and verified the recognition mechanism of compound 1 through density functional theory (DFT) calculation. Compound 1 was successfully used to detect Hg2+ in actual water samples, the recovery was 91 %–106 %, and the relative standard deviation (R.S.D.) was less than 2.5 %, which provided possibility for compound 1 to be used as a sensor in environmental research. [ABSTRACT FROM AUTHOR]

Alkalized CN photocatalyst with potassium doping is rationally designed to realize selective co-production of dihydroxyacetone and glyceric acid, resulting in >70 % glycerol conversion and >70 % total selectivity from glycerol photo-oxidation process. [Display omitted] • The alkalized CN with K doping is synthesized via a facile calcination process. • Co-production of dihydroxyacetone and glyceric acid via glycerol photo-oxidation. • Glycerol conversion (>80 %) and co-production selectivity (>70 %) can be achieved. • Superior performance of modified CN for glycerol oxidation is demonstrated by DFT. The emergence of biomass valorization holds great promise in tackling the energy crisis and promote carbon neutrality. Mild and cost-effective photocatalysis offers notable advantages in terms of energy efficiency, environmentally friendly, and facile processes. Here, we demonstrate selective glycerol photo-oxidation for dihydroxyacetone (DHA) and glyceric acid (GLA) co-production by strategically engineering potassium-doped alkalized polymeric carbon nitride (CN). The altered CN demonstrates promoted absorption of visible light, increased efficiency in separating charges, and superior deprotonating functionality of glycerol. Density functional theory (DFT) calculations further certificate its superior performance for glycerol oxidation into DHA and GLA. As a result, the rationally-constructed CN achieves exceptional glycerol conversion (>70 %) and maintains total selectivity of DHA and GLA (>70 %) at room temperature. This study showcases the viability of selective glycerol photo-oxidation for co-production of high-value chemicals under mild operating conditions. [ABSTRACT FROM AUTHOR]

Biomass photorefining is a promising approach for sustainable clean energy and high-value chemical production. However, selectively converting glucose into glucaric acid, the most valuable derivative, still poses a significant challenge due to the difficulty in transforming the terminal hydroxyl group into a carboxy group. Here, we demonstrate that highly selective glucose photorefining into glucaric acid can be achieved by synergistically coupling alkalizing modification of polymeric carbon nitride (CN) with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) mediation, which promotes the oxidation of the primary alcohol group attached to the C6 site of gluconic acid. Density functional theory (DFT) calculations affirm the enhanced performance of modified CN in glucaric acid production. When medicated with TEMPO, the optimized photocatalysis achieves ∼ 100 % glucose conversion and > 30 % glucaric acid yield, setting a record for photocatalytic glucaric acid production. This work showcases the significance of combining photocatalyst modification and redox mediation for inspiring high-efficiency photocatalysis systems for biomass photorefining. [Display omitted] • Alkalized CN with potassium doping synthesized through simple calcination. • Constructed synergistic system of photocatalyst and organocatalyst. • Achieved highest reported glucaric acid yield (> 30 %) via photocatalysis. • Proven superior performance of modified CN for glucaric acid production by DFT. [ABSTRACT FROM AUTHOR]