Search

• A common carbon nitride delivers great 2eORR activity for H 2 O 2 production in presence of lactic acid as sacrificial agent. • Pyruvic acid is simultaneously produced from selective dehydrogenation of lactic acid. • Other hydroxycarboxylic acids are selectively dehydrogenated into corresponding aldehydic or keto acids. • In-depth experimental and theoretical investigations reveal the detailed reaction mechanism. Photocatalytic H 2 O 2 production is emerging as an alternative technology to contribute H 2 O 2 -based advanced oxidation applications. However, the present reaction systems rarely consider the selective oxidation of sacrificial agent along with oxygen reduction reaction. Herein, we design a reaction system by using hydroxycarboxylic acids as additives to boost photocatalytic H 2 O 2 production. More importantly, hydroxycarboxylic acids could simultaneously be dehydrogenated into aldehydic/keto acids with high selectivity. Lactic acid as one of the typical hydroxycarboxylic acids reveals the feasibility of this hypothesis, delivering 6.56 mM/h of H 2 O 2 generation along with > 70 % pyruvic acid selectivity. The universality of this reaction system is demonstrated by using other hydroxycarboxylic acids. This works sheds new light on coupling H 2 O 2 generation with value-added chemicals production by mild photocatalytic approach. [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]

[Display omitted] • Two fused-ring electron acceptors based on eight thiophene rings are developed. • The developed acceptors exhibit strong near-infrared absorption beyond 1000 nm. • The effects of core-extension and terminal fluorination have been investigated. • Terminal fluorination has a greater impact on molecular photoelectric properties. • 6TIC-4F device achieved one of the highest PCE among narrow bandgap acceptors. Understanding the relationship between the molecular structure and photoelectric properties of fused-ring non-fullerene acceptors (NFAs) is of far-reaching significance to the development of organic solar cells (OSCs). Herein, six NFAs based on multiple thiophenes (4 T, 6 T and 8 T) are employed to systematically probe the synergistic effects of extending central core size and terminal fluorination. The absorption results manifest that the molecular absorption is comprehensively affected by molecular crystallinity, planarity, conjugation length and intramolecular electron push–pull effect, simultaneously. The intensity of electron push–pull effect is not only related to the electron-donating ability of central core and the electron-withdrawing ability of end group, but also may be related to the distance between the positive and negative centers. The extension of central core leads to the more planar backbone and stronger crystallinity of NFAs, and less energy loss (E loss) in its based OSC. Compared with the extension of central core, terminal fluorination has a greater impact on molecular photoelectric properties. The terminal fluorination significantly enhances the push–pull effect, lowers the energy levels, and slightly increases the vibrational relaxation. As a result, the strongest crystallinity and coplanarity of 8TIC-4F lead to a low vibrational relaxation of 0.18 eV, which makes PTB7-Th:8TIC-4F device exhibit a small E loss of 0.51 eV and a high efficiency of 10.4%. In addition, the fluorinated 6TIC-4F with suitable core size exhibits suitable energy level, absorption, crystallization, and phase separation morphology, making its as-cast device up to 11.61% efficiency. To the best of the authors' knowledge, the PCE of 11.61% for PTB7-Th:6TIC-4F based device without any treatment is one of the highest values reported for the NAFs with over 1000 nm absorption. [ABSTRACT FROM AUTHOR]

Enhanced visible-light-driven porous O/P-C 3 N 4 for persulfate photoactivation to remove refractory organic pollutants (bisphenol A and 2-mercaptobenzothiazole) and depolymerize lignin to vanillic acid and various gases. [Display omitted] • Surface electron density on HAPA-CN was enhanced by oxygen and phosphorus doping. • 0.05 HAPA-CN exhibits excellent performance for persulfate photoactivation to remove BPA and MBT. • In-depth exploration of the intermediate products during the photodegradation. • Remarkable sodium lignosulfonate conversion and vanillic acid selectivity achieved. • The transformation of sodium lignosulfonate synergistically produces a variety of gases (H 2 , CO, CH 4 , C 2 H 4 , C 2 H 6). In this research, an enhanced visible light response of oxygen and phosphorus-doped porous g-C 3 N 4 (HAPA-CN) was prepared by thermo-polymerization of urea, hydroxyacetic acid and phytic acid. Its internal structure was verified by solid-state nuclear magnetism (NMR) and secondary ion mass spectrometry (SIMS). The surface electron density on HAPA-CN was enhanced by the inclusion of oxygen and phosphorus. The boosted photocatalytic activity was attributed to the high spectral utilization of sunlight and meliorated charge separation efficiency. The experimental results showed that the 0.05 HAPA-CN/persulfate (PS) system exhibited a higher efficiency in the photodegradation process of bisphenol A (BPA) and 2-mercaptobenzothiazole (MBT). Compared with ordinary g-C 3 N 4 , the integration of photocatalysis and persulfate oxidation led to an increase in the removal of BPA and MBT pollutants, which increased by 68.11 and 11.18 times, respectively. 0.05 HAPA-CN also exhibited a certain photodegradation of BPA under long-wavelength light irradiation such as blue, green, and red light. In the photocatalytic conversion of sodium lignosulfonate (SL), the 0.05 HAPA-CN/PS system achieved a maximum yield of 134.34 mg/g SL vanillic acid at 30 min, which was significantly better than that of g-C 3 N 4. Synergistic gas production (H 2 , CO, CH 4 , C 2 H 4 , C 2 H 6) was also significantly enhanced. Combined with theoretical calculations, the mechanism was also analyzed. This work provides new insights for exploring high efficiency photocatalyst that combine porous structure, oxygen and phosphorus co-doping and PS activation technology for removal of organic pollutants and lignin valorization. [ABSTRACT FROM AUTHOR]

[Display omitted] • The PtO@Ti 3 C 2 /TiO 2 composite is obtained via Ti 3 C 2 MXene in-situ conversion and following PtO nanodots photo-deposition. • The Ti 3 C 2 MXene and PtO nanodots effectively separate the photogenerated electrons and holes. • The PtO nanodots also largely suppress the hydrogen back reaction. • The PtO@Ti 3 C 2 /TiO 2 composite demonstrates remarkable photocatalytic H 2 production efficiency. Increasing the separation efficiency of photogenerated carriers and preventing the hydrogen back oxidation are two key challenges in photocatalytic hydrogen production. Herein, we report a promising PtO@Ti 3 C 2 /TiO 2 photocatalyst to overcome these two challenges by in-situ growing TiO 2 nanosheets on Ti 3 C 2 MXene (to improve charge separation) and depositing PtO nanodots (to diminish hydrogen back reaction) for enhanced photocatalytic hydrogen production. Within this design principle, the photogenerated electrons and holes in the PtO@Ti 3 C 2 /TiO 2 composites flow in opposite direction into PtO and Ti 3 C 2 respectively, resulting in effective separation of the photogenerated electrons and holes. Beyond, the higher oxidation state of PtO nanodots also largely suppresses the undesirable hydrogen back oxidation reaction. Thereby the PtO@Ti 3 C 2 /TiO 2 composite demonstrates remarkable hydrogen production efficiency. Our work here indicates that rational design of dual co-catalysts could not only promote the separation of photogenerated carriers for enhanced hydrogen production, but also inhibit the reverse reaction of hydrogen production. [ABSTRACT FROM AUTHOR]

• Toxic inhibition was explored as a potential control strategy to achieve stable nitritation. • The inherent toxic pollutants in the coking wastewater were utilize to eliminate NOB. • A mathematical model was developed to resolve the feasible OLR range for nitrite accumulation. • A joint OLR region of 0.80–1.35 kg·m−3d−1 was found favorable for nitritation. • DO regulation further benefit in achieving partial nitritation. The presence of toxic compounds in coking wastewater is challenging for water treatment, but it also offers opportunities for the selection of specific bacterial populations based on different sensitivities. The potential selective inhibitory effect of toxic compounds in coking wastewater was employed here to inhibit nitrite oxidizing bacteria (NOB), allowing stable nitritation in a long-term experiment using a biological fluidized bed reactor. The main challenge was to identify the appropriate toxic compound loading range that would effectively inhibit NOB but allow ammonium oxidizing bacteria (AOB) to work, by variation of organic loading rate (OLR) and dissolved oxygen (DO). An OLR of 0.80–1.35 kg·m−3d−1 permitted nitritation with a nitrite accumulation rate (NAR) above 80.5%. DO regulation was used to control the extent of nitritation which resulted in different NH 4 +-N/NO 2 −-N ratios. The bacterial populations present under the various operation conditions were characterized by high-throughput sequencing, demonstrating presence of Nitrosomonas species as the main AOB, while Nitrospira species (typical NOB) were successfully suppressed. Batch activity experiments with the sludge demonstrated stronger inhibition from SCN− on NOB (IC 50 = 40.01 mg·L−1) than on AOB (IC 50 = 308.12 mg·L−1). A mathematical model was developed based on the differential inhibition by SCN− and phenol on NOB and AOB, which predicted the optimal conditions for stable nitritation, in line with the experimental data. These findings may help to promote the design and optimization of operation condition for nitritation of coking wastewater, and has potential for nitrogen removal via nitrite (e.g. Anammox) in the treatment of industrial wastewater containing toxic compounds. [ABSTRACT FROM AUTHOR]