Covalent coupling promoting charge transport of CdSeTe/UiO-66 for boosting photocatalytic CO_(2)reduction

Quantum dots(QDs)based heterojunction is a candidate for the photocatalytic CO_(2)reduction,owing to the large extinction coefficient and easy modification of band structures.However,the van der Waals interaction causes the large charge resistance and strong recombination centers between QDs and host materials,which makes the poor photocatalytic performance.Herein,a covalent bonded CdSeTeQDs and NH_(2)-UiO-66 heterojunction(NUC-x)is constructed through an acylamino(-CONH-).The results indicate that the acylamino between NH_(2)-UiO-66 and Cd Se Te QDs can serve as the transfer channels for the photogenerated charges and stabilize the QDs.The optimized NUC-1200 achieved a CO generation rate of 228.68μmol/g,which is 13 and 4 times higher than that of NH_(2)-UiO-66 and Cd Se Te QDs,respectively.This work provides a new avenue for efficient and stable photocatalysis of QDs.

Degradation of 4-nitrophenol by electrocatalysis and advanced oxidation processes using Co3O4@C anode coupled with simultaneous CO2 reduction via SnO2/CC cathode

Herein,we prepa red novel three-dimensional(3D)gear-s haped Co3O4@C(Co3O4 modified by amorphous carbon)and sheet-like SnO2/CC(SnO2 grow on the carbon cloth)as anode and cathode to achieve efficient removal of 4-nitrophenol(4-NP)in the presence of peroxymonosulfate(PMS)and simultaneous electrocatalytic reduction of CO2,respectively.In this process,4-NP was mineralized into CO2 by the Co3O4@C,and the generated CO2 was reduced into HCOOH by the sheet-like SnO2/CC cathode.Compared with the pure Co0.5(Co3O4 was prepared using 0.5 g urea)with PMS(30 mg,0.5 g/L),the degradation efficiency of 4-NP(60 mL,10 mg/L)increased from 74.5%-85.1%in 60 min using the Co0.5 modified by amorphous carbon(Co0.5@C).Furthermore,when the voltage of 1.0 V was added in the anodic system of Co0.5@C with PMS(30 mg,0.5 g/L),the degradation efficiency of 4-NP increased from 85.1%-99.1%when Pt was used as cathode.In the experiments of 4-NP degradation coupled with simultaneous electrocatalytic CO2 reduction,the degradation efficiency of 4-NP was 99.0%in the anodic system of Co0.5@C with addition of PMS(30 mg,0.5 g/L),while the Faraday efficiency(FE)of HCOOH was 24.1%at voltage of-1.3 V using the SnO2/CC as cathode.The results showed that the anode of Co3O4 modified by amorphous carbon can markedly improve the degradation efficiency of 4-NP,while the cathode of SnO2/CC can greatly improve the FE and selectivity of CO2 reduction to HCOOH and the stability of cathode.Finally,the promotion mechanism was proposed to explain the degradation of organic pollutants and reduction of CO2 into HCOOH in the process of electrocatalysis coupled with advanced oxidation processes(AOPs)and simultaneous CO2 reduction.

High-Loading Fe Single-Atom Catalyst for 100% Selectivity of ^(1)O_(2) Generation

As promising approaches in wastewater treatment, advanced oxidation processes(AOPs) can efficiently degrade and mineralize the organic wastes and contaminants by generating reactive radicals like ·OH, ·SO_(4)^(-), and ·O_(2)^(-). However, due to the stronger oxidability, these reactive radicals exhibit lower selectivity of degradation.

Semi-chemical interaction between graphitic carbon nitride and Pt for boosting photocatalytic hydrogen evolution

Owing to the exorbitant overpotential and serious carrier recombination of graphitic carbon nitride(gC_(3)N_(4)),noble metal(NM)is usually served as the H_(2)evolution co-catalyst.Although the NM(such as Pt)nanoparticles can reduce the H_(2)evolution overpotential,the weak van der Waals interaction between Pt and g-C_(3)N_(4)makes against the charge transfer.Herein,the solvothermal method is developed to achieve semi-chemical interaction between Pt and g-C_(3)N_(4)nanotube(Pt-CNNT)for fast charge transfer.Moreover,the generated in-plane homojunction of CNNT can accelerate charge separation and restrain recombination.Meanwhile,the metallic Pt is an excellent H_(2)evolution co-catalyst.Photo/electrochemical tests verify that the semi-chemical interaction can improve photogenerated charge separation and transferability of CNNT.As a result,the photocatalytic H_(2)evolution turnover frequency(TOF)of Pt-CNNT under visible light irradiation reaches up to 918 h^(-1),which is one of the highest in the g-C_(3)N_(4)-based photocatalysts.This work provides a new idea to improve the charge transfer for efficient photocatalytic H_(2)evolution.

Sodium-doped carbon nitride nanotubes for efficient visible light-driven hydrogen production

Sodium-doped carbon nitride nanotubes （Nax-CNNTs） were prepared by a green and simple two-step method and applied in photocatalytic water splitting for the first time. Transmission electron microscopy （TEM） element mapping and X-ray photoelectron spectroscopy （XPS） measurements confirm that sodium was successfully introduced in the carbon nitride nanotubes （CNNTs）, and the intrinsic structure of graphitic carbon nitride （g-C3N4） was also maintained in the products. Moreover, the porous structure of the CNNTs leads to relatively large specific surface areas. Photocatalytic tests indicate that the porous tubular structure and Na＋ doping can synergistically enhance the hydrogen evolution rate under visible light （λ 〉 420 nm） irradiation in the presence of sacrificial agents, leading to a hydrogen evolution rate as high as 143 μmol·h-1 （20 mg catalyst）. Moreover, other alkali metal-doped CNNTs, such as Lix-CNNTs and Kx-CNNTs, were tested; both materials were found to enhance the hydrogen evolution rate, but to a lower extent compared with the Nax-CNNTs. This highlights the general applicability of the present method to prepare alkali metal-doped CNNTs; a preliminary mechanism for the photocatalytic hydrogen evolution reaction in the Nax-CNNTs is also proposed.