Developing diatomic catalysts (DACs)
for the CO2 reduction
reaction (CO2RR) has emerged as a promising leading-edge
research area owing to their maximum atomic utility and more sophisticated
functionalities. However, the proper design of DACs at an atomic level
and an understanding of the synergistic mechanism of binary sites
remain challenging. Herein, an N-rich carbon matrix with precisely
controlled Ni/Cu dual sites is synthesized through the assistance
of metal–organic frameworks. The as-prepared catalyst presents
high CO Faradaic efficiency of over 95% from −0.39 to −1.09
V vs reversible hydrogen electrode (RHE) with the maximum value of
99.2% at −0.79 V vs RHE and long-term durability of 60 h electrolysis.
Density functional theory studies reveal that the electronic redistribution
and band gap narrowing induced by the adjacent NiN4 and
CuN4 moieties enhance the electron conductivity and strengthen
the bonding interactions between *COOH intermediates and Ni centers,
thus lowering the overall reaction barriers and promoting CO generation.
The diatomic catalysts (DACs) provide a new strategy for efficient catalysis of CO2 reduction reaction (CO2RR) owing to their maximum atomic utility and more flexible active sites. However, it is...
A comb-shape
amphiphilic cationic side chain is proposed to well-balance
the water sorption in anion exchange membranes (AEMs), in which the
cationic group is in between of an ether-containing hydrophilic spacer
and an alkyl hydrophobic spacer. By fully grafting the amphiphilic
side chains onto polybenzimidazole (PBI), comb-shape amphiphilic microphase
networks are well-developed in the AEMs, in which the alkyl hydrophobic
network greatly restricts water swelling and the ether-containing
hydrophilic network keeps the hydration of the cationic groups and
enlarges the ion conductive channel. The as-prepared membranes achieve
a high conductivity of about 91.2 mS cm–1, an extremely
low swelling ratio of about 8.1% at 80 °C, and good mechanical
properties at a hydrated state (tensile strength and elongation at
a break of about 14.6 MPa and 77.5%, respectively). Benefits from
the balanced water sorption in AEMs, the H2/O2 fuel cell with a 10 μm ultrathin membrane could withstand
80 °C and 0.1 MPa back pressure and achieve a high open circuit
voltage of about 1.0 V and a high peak power density of about 631.5
mW cm–2. This work provides a new insight into the
design of high-performance AEM.
N-doped porous carbon (NC) could be synthesized route from sugar cane bagasse, which are sustainable and widely available biomass waste. Preferred NC sample has a well-developed porous structure, the graphene-like...
Green tides are caused by the proliferation of chlorophytes under suitable hydrographic conditions. These blooms lead to environmental degradation and negatively impact the waters and seagrass beds, as well as fishing and other recreational activities in the bay. A comprehensive ecological understanding of the bloom dynamics, including the origin and persistence, is needed to foster management decisions. The algae in the great majority of green tide blooms usually belong to two genera of Ulvophyceae, Ulva and Enteromorpha. Ulva has been observed more often in recent years. In China, green tides occurred for the first time in the middle area of the Yellow Sea in 2007, and a large-scale algae blooming broke out in the middle and southern areas of the Yellow Sea in late May 2008. We identified them as Ulva prolifera by comparative analysis of the rDNA internal transcribed spacer 1 (ITS1), 5.8S and ITS2 sequences in combination with microscopic observation. Morphological differences were found between the free-floating algae and the attached thalli. Various reproduction patterns of the free-floating algae include sexual, asexual and vegetative propagations, which played important roles in the long-term green tide persistence in China. The ITS sequences of the blooming algae were identical to those of the samples from the Lianyungang sea area but were different from the attached samples from the Qingdao sea area. The results infer that the blooms are originated from other sea areas rather than from the local attached populations.
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