Jinjia Liu

Oxide-Modified Nickel Photocatalysts for the Production of Hydrocarbons in Visible Light

Metallic nickel nanostructures that were partially decorated by discrete nickel oxide layers were fabricated by in situ reduction of calcinated Ni-containing layered double hydroxide nanosheets, the structure of which was confirmed by extended X-ray absorption fine structure spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The existence of the abundant interfaces between the surface Ni oxide overlayer and metallic Ni altered the geometric/electronic structure of the Ni nanoparticles, making them apt for CO activation under light irradiation. Most importantly, the unique structure favors the C-C coupling reaction on its surface, which confers the catalyst unexpected reaction power towards higher hydrocarbons at moderate reaction conditions. This study leads to a green and sustainable approach for the photocatalytic production of highly valuable chemical fuels.

Supramolecular Porphyrin Cages Assembled at Molecular-Materials Interfaces for Electrocatalytic CO Reduction

Conversion of carbon monoxide (CO), a major one-carbon product of carbon dioxide (CO2) reduction, into value-added multicarbon species is a challenge to addressing global energy demands and climate change. Here we report a modular synthetic approach for aqueous electrochemical CO reduction to carbon–carbon coupled products via self-assembly of supramolecular cages at molecular–materials interfaces. Heterobimetallic cavities formed by face-to-face coordination of thiol-terminated metalloporphyrins to copper electrodes through varying organic struts convert CO to C2 products with high faradaic efficiency (FE = 83% total with 57% to ethanol) and current density (1.34 mA/cm2) at a potential of −0.40 V vs RHE. The cage-functionalized electrodes offer an order of magnitude improvement in both selectivity and activity for electrocatalytic carbon fixation compared to parent copper surfaces or copper functionalized with porphyrins in an edge-on orientation.

Co-Based Catalysts Derived from Layered-Double-Hydroxide Nanosheets for the Photothermal Production of Light Olefins

Solar-driven Fischer-Tropsch synthesis represents an alternative and potentially low-cost route for the direct production of light olefins from syngas (CO and H2 ). Herein, a series of novel Co-based photothermal catalysts with different chemical compositions are successfully fabricated by H2 reduction of ZnCoAl-layered double-hydroxide nanosheets at 300-700 °C. Under UV-vis irradiation, the photothermal catalyst prepared at 450 °C demonstrates remarkable CO hydrogenation performance, affording an olefin (C2-4= ) selectivity of 36.0% and an olefin/paraffin ratio of 6.1 at a CO conversion of 15.4%. Characterization studies using X-ray absorption fine structure and high-resolution transmission electron microscopy reveal that the active catalyst comprises Co and Co3 O4 nanoparticles on a ZnO-Al2 O3 mixed metal oxide support. Density functional theory calculations further demonstrate that the oxide-decorated metallic Co nanoparticle heterostructure weakens the further hydrogenation ability of the corresponding Co, leading to the high selectivity to light olefins. This study demonstrates a novel solar-driven catalyst platform for the production of light olefins via CO hydrogenation.

Eutrophication as a driver of r-selection traits in a freshwater fish.

This study tested whether eutrophication could influence life-history traits of a cyprinid, Chanodichthys erythropterus, in 10 Chinese lakes. Using the von Bertalanffy growth model, the asymptotic length (L∞ ) and the growth performance index (IGRO ) were significantly affected by eutrophication. The gonado-somatic index (IG ) and relative fecundity (FR ) were significantly lower in mesotrophic lakes than in eutrophic and hypertrophic lakes. These results indicate that increasing eutrophication affects the life-history tactics of a freshwater fish.

Rapid growth increases intrinsic predation risk in genetically modified Cyprinus carpio: implications for environmental risk

The intrinsic effect of feeding regime on survival and predation-induced mortality was experimentally tested in genetically modified (GM) Cyprinus carpio and wild specimens. The results clearly indicate a knock-on effect of the GH gene (gcGH) introduction into the C. carpio genome on their vulnerability to predation. The experiments unequivocally showed that it is the genetic nature of the C. carpio rather than its size that affects the risk of predation. In addition, fed C. carpio were more susceptible to predation risk. Thus, the study characterizes the existence of a trade-off between somatic growth and predator avoidance performance. Current research in Europe suggests that high uncertainty surrounding the potential environmental effects of escapee transgenic fishes into the wild is largely due to uncertainty in how the modified gene will be expressed. Understanding variables such as the cost of rapid growth on antipredator success would prove to be pivotal in setting up sound risk assessments for GM fishes and in fully assessing the environmental risk associated with GM fish escapees.

Tuning Gold Nanoparticles with Chelating Ligands for Highly Efficient Electrocatalytic CO2 Reduction

Capped chelating organic molecules are presented as a design principle for tuning heterogeneous nanoparticles for electrochemical catalysis. Gold nanoparticles (AuNPs) functionalized with a chelating tetradentate porphyrin ligand show a 110-fold enhancement compared to the oleylamine-coated AuNP in current density for electrochemical reduction of CO2 to CO in water at an overpotential of 340 mV with Faradaic efficiencies (FEs) of 93 %. These catalysts also show excellent stability without deactivation (<5 % productivity loss) within 72 hours of electrolysis. DFT calculation results further confirm the chelation effect in stabilizing molecule/NP interface and tailoring catalytic activity. This general approach is thus anticipated to be complementary to current NP catalyst design approaches.

Reductive Transformation of Layered-Double-Hydroxide Nanosheets to Fe-Based Heterostructures for Efficient Visible-Light Photocatalytic Hydrogenation of CO

Conversion of syngas (CO, H2 ) to hydrocarbons, commonly known as the Fischer-Tropsch (FT) synthesis, represents a fundamental pillar in todays chemical industry and is typically carried out under technically demanding conditions (1-3 MPa, 300-400 °C). Photocatalysis using sunlight offers an alternative and potentially more sustainable approach for the transformation of small molecules (H2 O, CO, CO2 , N2 , etc.) to high-valuable products, including hydrocarbons. Herein, a novel series of Fe-based heterostructured photocatalysts (Fe-x) is successfully fabricated via H2 reduction of ZnFeAl-layered double hydroxide (LDH) nanosheets at temperatures (x) in the range 300-650 °C. At a reduction temperature of 500 °C, the heterostructured photocatalyst formed (Fe-500) consists of Fe0 and FeOx nanoparticles supported by ZnO and amorphous Al2 O3 . Fe-500 demonstrates remarkable CO hydrogenation performance with very high initial selectivities toward hydrocarbons (89%) and especially light olefins (42%), and a very low selectivity towards CO2 (11%). The intimate and abundant interfacial contacts between metallic Fe0 and FeOx in the Fe-500 photocatalyst underpins its outstanding photocatalytic performance. The photocatalytic production of high-value light olefins with suppressed CO2 selectivity from CO hydrogenation is demonstrated here.