Novel 2D photocatalyst of copper-doped carbon quantum dot CD(Cu) loaded with ultrathin Ni-MOL for degradation of tetracycline.

Broadening the light absorption range and suppressing the carrier complexation are the two keys to enhance the photocatalytic activity. In this work, a novel two-dimensional (2D) photocatalyst was successfully prepared by modified hydrothermal method and applied in tetracycline (TC) degradation. The degradation rate of CD(Cu)-Ni-MOL for TC reached 93.5% within 60 min under the visible light condition. The improved photocatalytic performance of CD(Cu)-Ni-MOL was attributed to the constructed 2D layered structure and the special properties of CD(Cu). The doped Cu in carbon dots (CDs) exhibited excellent photocatalytic performance among the elements of Cu, Zn, Ni, Co and Fe. The order of photocatalytic performance improvement was Cu > Zn > Ni > Co > Fe. In addition, a possible degradation pathway for TC was proposed. This work confirms the great potential of CD(Cu)-Ni-MOL as a highly efficient photocatalyst in removing tetracycline pollutants in water.

Ni-MOL/In2Se3 heterostructure construction with mixed metal (Ti/Ni) for efficient photocatalytic tetracycline degradation.

To investigate the mechanism of bimetallic 2-dimension (2D) catalyst existing in the current photocatalytic degradation process, the tetracycline (TC) degradation performance and mechanism by bimetallic 2D photocatalyst was studied extensively. Nickel metal-organic layer (Ni-MOL) and In2Se3, a typical 2D semiconductor photocatalyst, shows great potential for photocatalytic degradation of TC. Herein, an In2Se3 assisted Ni-MOL composite bimetallic photocatalyst was assembled, of which could obtain the degradation rate of 96.4% within 90 min for TC under visible light. Ni-MOL was the main active site for TC degradation by photo-induced holes which located at the Ni atom active site during the photocatalytic process. The role of In2Se3 and the element of Ti in Ni-MOL was to assist Ni-MOL by providing more photo-induced carriers and inhibiting carrier recombination. This work makes a contribution to the application of 2D bimetallic photocatalytic in TC degradation.

[Characteristics of Water Extractable Organic Nitrogen from Erhai Lake Sediment and Its Differences with Other Sources].

The 47 samples from Erhai Lake surface sediments were collected in different seasons. The distribution and structure characteristics of sediment water extractable organic nitrogen(WEON) were investigated by using the combined techniques of UV-Vis absorption and three-dimensional excitation-emission matrix spectra(3DEEMs). The differences in DON of various sources(overlying water, pore water, inflow Rivers and wet deposition) were explored to analyze its effects on sediment. The results showed that:1the temporal distribution followed the pattern of summer > spring > autumn > winter, with the spatial WEON distribution of northern > southern > central. 2 The humic degree of Erhai sediment WEON was relatively high and mostly composed of fulvic acid, which mainly contained UV-like humic-like fluorescence peak A and high-excited tryptophan fluorescence peak B. This indicated that it was mainly affected by terrestrial input and microbial activity. 3 There were two fluorescent components(C1, C2) in the sediments and other sources of Erhai Lake. The component C1 was the endogenous visible ultraviolet peak formed by biodegradation, while the component C2 was the tryptophan peak. The bioavailability of wet deposition samples was comparatively high, greatly impacting Erhai Lake in heavy rainfall. The DON bioavailability in the inflow river was the lowest, which was prone to be accumulated in sediments. 4The DON component C1 and C2 in overlying water had significant negative correlation with Erhai sediment WEON contents(r=-0.79, P<0.01;r=-0.944, P<0.01). This suggested that the overlying water DON components could indirectly reflect the sediment WEON content of Erhai Lake, namely the higher the fluorescence components C1 and C2 in overlying water DON were, the lower the sediment WEON content was.

Silver(I)-catalyzed carboxylation of arylboronic esters with CO2.

A variety of arylboronic esters were efficiently carboxylated with CO(2) using a simple AgOAc/PPh(3) catalyst, affording the corresponding carboxylic acids in good yield. This simple and efficient silver(i) catalytic system showed wide functional group compatibility.