Xiamen University

About: Xiamen University is a education organization based out in Amoy, Fujian, China. It is known for research contribution in the topics: Catalysis & Population. The organization has 50472 authors who have published 54480 publications receiving 1058239 citations. The organization is also known as: Amoy University & Xiàmén Dàxué.

Responses of marine primary producers to interactions between ocean acidification, solar radiation, and warming

Abstract: Anthropogenic CO2 is accumulating in the atmosphere and trapping reflected infrared radiation, resulting in warming of both terrestrial and ocean ecosystems. At the same time, the dissolution of CO2 into seawater is increasing surface ocean acidity, a process known as ocean acidification. Effects of ocean acidification on marine primary producers have been docu- mented to be stimulative, inhibitive, or neutral. Elevated CO2 and reduced pH levels can interact with solar radiation, which fluctuates over different time scales from limiting to saturating or even stressful levels, to bring about synergistic, antagonistic, or balanced effects on marine primary producers at different depths or under changing weather conditions. However, shoaling of the upper mixed layer (enhanced stratification) due to ocean warming and freshening (rain, ice melt- ing) can lead to additional photosynthetically active radiation (PAR) and ultraviolet (UV) expo- sure, which can have both benefits and costs to photosynthetic organisms. Elevated CO2 concen- trations under low or moderate levels of PAR have been shown to enhance photosynthesis or growth of both phytoplankton and macroalgae; excessive levels of PAR, however, can lead to additional inhibition of photosynthesis or growth under elevated CO2, and addition of UV radia- tion (280 to 400 nm) can increase or down-regulate such inhibition, since solar UV-B (280 to 315 nm) radiation often harms algal cells, while UV-A (315 to 400 nm) at moderate levels stimu- lates photosynthetic carbon fixation in both phytoplankton and macroalgae. In view of warming effects, increased temperatures have been shown to enhance photorepair of UV-damaged mole- cules, though it simultaneously enhances respiratory carbon loss. The net effects of ocean acidifi- cation on marine primary producers are therefore largely dependent on the photobiological con- ditions (light limitation, light or UV stress), as well as interactions with rising temperature and other variables such as altered nutrient availability. Hence, feedbacks between changing carbon- ate chemistry and solar radiation across the entire spectrum present complications to interpret and understand ocean acidification effects based on single-factor experiments.

Semiconductive Copper(I)–Organic Frameworks for Efficient Light‐Driven Hydrogen Generation Without Additional Photosensitizers and Cocatalysts

Abstract: The rational design of completely cocatalyst-free and self-sensitized photocatalytic systems for splitting water into hydrogen is a subject of new research. As the first example without additional cocatalysts and photosensitizers, the comparatively cost-effective Cu2I2-based MOF Cu-I-bpy, exhibited a high-efficiently photocatalytic hydrogen production (7.09 mmol·g-1·h-1). DFT calculations established the electronic structures of Cu-I-bpy with a narrow band gap of 2.05 eV, indicating its semi-conductive behavior, which was well consistent with the experimental value of 2.00 eV. The proposed mechanism demonstrates that Cu2I2 clusters of Cu-I-bpy serve as photoelectron generators to accelerate the copper(I) hydrides interaction, providing redox reaction sites for hydrogen evolution. The highly stable cocatalyst-free and self-sensitized Cu-I-bpy provides new insights into the design of cost-effective d10-based MOFs for high-efficient and long-term solar fuels production in future.

Influence of steric hindrance of organic ligand on the structure of Keggin-based coordination polymer

Abstract: Five Keggin-based 3D coordination polymers, namely, [Cu3(pz)3(PW12O40)] (pz = pyrazine) (1), [Cu3(2,3-Me2pz)3(PW12O40)] (2,3-Me2pz = 2,3-dimethylpyrazine) (2), [Cu2(2,5-Me2pz)1.5(2,5-HMe2pz)(PW12O40)] (2,5-Me2pz = 2,5-dimethylpyrazine) (3), [Cu3(2,3-Me2pz)3(PMo12O40)] (4), and [Ag3(pz)3(PW12O40)]·0.5H2O (5), were synthesized and structurally characterized. Crystal data are as follows: trigonal, space group R3c, a = 18.4070(14) A, c = 22.544(3) A, γ = 120°, and Z = 6 for 1; orthorhombic, space group Pccn, a = 16.599(2) A, b = 20.470(3) A, c = 14.3757(18) A, and Z = 4 for 2; triclinic, space group P1, a = 10.667(2) A, b = 11.147(2) A, c = 20.207(4) A, α = 90.983(4)°, β = 108.128(3)°, γ = 92.150(4)°, and Z = 2 for 3; orthorhombic, space group Pccn, a = 16.450(3) A, b = 20.170(4) A, c = 14.244(3) A, and Z = 4 for 4; and rhombohedral, space group R32, a = 18.2047(13) A, c = 23.637(3) A, γ = 120°, and Z = 6 for 5. Their structural differences were investigated using crystal structure analysis, revealing that...