Catalytic transfer hydrogenation of levulinate ester intoγ-valerolactone over ternary Cu/ZnO/Al2O3 catalyst

An effective catalytic transfer hydrogenation (CTH) process of bio-based levulinate esters into γ-valerolactone (GVL) was explored over ternary Cu/ZnO/Al2O3 catalyst which was prepared by coprecipitation method and could be sustainably used. As a result, quantitative conversion of ethyl levulinate (EL) and 99.0% yield of GVL were obtained in the CTH process using i-PrOH as hydrogen donor. The Cu/ZnO/Al2O3 catalyst with high-surface-area could be reused at least four times without the loss of catalytic activity. Furthermore, the structure and properties of Cu/ZnO/Al2O3 catalyst was characterized through XRD, BET, SEM, TEM and H2-TPR. Also, the influence of different support oxides and calcination temperatures was investigated.

Catalytic conversion of ethyl lactate to 1,2-propanediol over CuO

An efficient conversion of biomass-derived ethyl lactate to 1,2-propanediol(1,2-PDO) over CuO was investigated.Among the catalysts we tested, CuO, Cu2 O and Co showed excellent catalytic activity for the conversion of ethyl lactate to 1,2-PDO in water, and CuO was more active and gave the best result. The 1,2-PDO yield of 93.6% was achieved when Zn acted as a reductant. The results indicated that in situ formed hydrogen by the oxidation of Zn in water is more effective than gaseous hydrogen, which failed to produce the 1,2-PDO from ethyl lactate.From a practical point of view, the present method may provide a useful route for the production of 1,2-PDO from ethyl lactate.

Improved two-step hydrothermal process for acetic acid production from carbohydrate biomass

An improved two-step process for converting carbohydrate biomass to acetic acid under hydrothermal conditions is proposed. The first step consists of the production of lactic acid from carbohydrate biomass, and the second step consists of conversion of the lactic acid obtained in the first step to acetic acid using CuO as an oxidant. The results indicated that CuO as an oxidant in the second step can significantly improve the production of high-purity acetic acid from lactic acid, and the maximum yield of acetic acid was 61%, with a purity of 90%. The yield of acetic acid obtained using the improved two-step hydrothermal process from carbohydrate biomass, such as glucose, cellulose and starch, was greater than that obtained using traditional two-step process with H_2O_2 or O_2. In addition, a proposed pathway for the production of acetic acid from lactic acid in the second step with CuO was also discussed. The present study provides a useful two-step process for the production of acetic acid from carbohydrate biomass.

Highly-efficient and autocatalytic reduction of NaHCO_3 into formate by in situ hydrogen from water splitting with metal/metal oxide redox cycle

The Earth’s sustainable development is threatened by the increasing atmospheric COlevel which can be attributed to the imbalance of COdue to the rapid consumption of fossil fuels caused by human activities and the slow absorption and conversion of COby nature. One of the efficient methods for reconstructing the balance of COshould involve the rapid conversion of COinto fuels and chemicals.The hydrogenation of COwith gaseous hydrogen is currently considered to be the most commercially feasible synthetic route, however, the supply of safe and economical hydrogen sources poses a significant challenge to up-scaling application. Direct utilization of hydrogen from dissociation of water, the most abundant, cheap and clean hydrogen resource, for the reduction of COwould be one of the most promising approaches for COutilization. This paper provides an overview of the current advances in research on highly efficient reduction of COor NaHCO, a representative compound of CO, into formic acid/formate by in situ hydrogen from water dissociation with a metal/metal oxide redox cycle under mild hydrothermal conditions.

Mechanism study of reduction of CO_2 into formic acid by in-situ hydrogen produced from water splitting with Zn: Zn/ZnO interface autocatalytic role

We have previously developed a new process of highly efficient conversion of COand water into formic acid with metallic Zn without the addition of catalyst, however, its mechanism is not clear, particularly in the catalytic role of Zn/ZnO interface. Herein, the autocatalytic role of Zn/ZnO interface formed in situ during the reduction of COinto formic acid with Zn in water was studied by combining high resolution transmission electron microscopy（HRTEM）, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS） techniques and experimental data. The electron microscope results show that possible defects or dislocations formed on Zn/ZnO interface, in which plays a key role for Zn H-formation. Further XPS analyses indicate that oxygen vacancies on Zn/ZnO interface increased at short reaction times（less than 10 min）. These analyses and experimental results suggest that a highly efficient and rapid conversion of COand water into formic acid should involve an autocatalytic role of the Zn/ZnO interface formed in situ, particularly at the beginning of the reaction.

Breeding of the New Hybrid Rape Variety Zhuoyou 1032 in Brassica napus L.

Zhuoyou 1032 is a new double-low hybrid rape variety in Brassica napus L.bred by Guizhou Zhuohao Agricultural Technology Co.,Ltd.in 2011 with the double-low two-type 240AB in B.napus L.as the female parent and the double-low restorer 132-4R as the male parent.In the adaptability evaluation test at 18 sites in two years,the average yield was 172.31 kg/666.7 m^2,which was 4.78% higher than that of Youyan 50 (CK);the whole growth period was about 202 d,which was earlier than Youyan 50 (CK) by 2-3 d;the plant height was 197.6 cm;the branching height was 52.1 cm;the number of effective branches was 5.55;the number of effective pods per plant was 179.7 (pods/plant);the number of seeds per pod was 17.7;the 1 000-seed weight was 3.99 g;and the average yield per plant was 11.7 g.It has the characteristics of early maturity,fast growth,good tidiness,compact plant type,moderate plant height,strong lodging resistance,strong resistance to sclerotinia rot,medium-to-long pods and large 1 000-seed weight.

Heterogeneous Cu_2O-mediated ethylene glycol production from dimethyl oxalate

An efficient process for the conversion of dimethyl oxalateinto ethylene glycol with high selectivity and high yield over CuO was investigated. In situ formed Cu as a true catalytically active species showed a good catalytic performance for DMO conversion to produce EG in 95% yield.

Revealing the GHG reduction potential of emerging biomass-based CO_(2) utilization with an iron cycle system

CO_(2) utilization becomes a promising solution for reducing anthropogenic greenhouse gas (GHG) emissions. Biomass-based CO_(2) utilization (BCU) even has the potential to generate negative emissions, but the corresponding quantitative evaluation is limited. Herein, the biomass-based CO_(2) utilization with an iron cycle (BCU-Fe) system, which converts CO_(2) into formate by Fe under hydrothermal conditions and recovers Fe with biomass-derived glycerin, was investigated. The GHG reduction potential under various process designs was quantified by a multidisciplinary method, including experiments, simulations, and an ex-ante life-cycle assessment. The results reveal that the BCU-Fe system could bring considerable GHG emission reduction. Significantly, the lowest value is −34.03 kg CO_(2)-eq/kg absorbed CO_(2) (−2.44 kg CO_(2)-eq/kg circulated Fe) with the optimal yield of formate (66%) and Fe (80%). The proposed ex-ante evaluation approach not only reveals the benefits of mitigating climate change by applying the BCU-Fe system, but also serves as a generic tool to guide the industrialization of emerging carbon-neutral technologies.

Organic carbon accumulation capability of two typical tidal wetland soils in Chongming Dongtan,China

We measured organic carbon input and content of soil in two wetland areas of Chongming Dongtan （Yangtze River Estuary） to evaluate variability in organic carbon accumulation capability in different wetland soils. Observed differences were investigated based on the microbial activity and environmental factors of the soil at the two sites. Results showed that the organic carbon content of wetland soil vegetated with Phragmites australis （site A） was markedly lower than that with P. australis and Spartina alterniflora （site B）. Sites differences were due to higher microbial activity at site A, which led to higher soil respiration intensity and greater carbon outputs. This indicated that the capability of organic carbon accumulation of the site B soils was greater than at site A. In addition, petroleum pollution and soil salinity were different in the two wetland soils. After bio-remediation, the soil petroleum pollution at site B was reduced to a similar level of site A. However, the culturable microbial biomass and enzyme activity in the remediated soils were also lower than at site A. These results indicated that greater petroleum pollution at site B did not markedly inhibit soil microbial activity. Therefore, differences in vegetation type and soil salinity were the primary factors responsible for the variation in microbial activity, organic carbon output and organic carbon accumulation capability between site A and site B.

Universally improving effect of mixed electron donors on the CO_2 fixing efficiency of non-photosynthetic microbial communities from marine environments

The universality of improved CO2 fixing upon the addition of mixed electron donors（MEDs）composed of Na2 S,NO2-,and S2O32-to non-photosynthetic microbial communities（NPMCs）obtained from 12 locations in four oceans of the world was validated. The CO2 fixing efficiencies of NPMCs were universally enhanced by MED compared with those obtained using H2 alone as electron donor,with average increase of about 276%. An increase in microbial inoculation concentration could increase the net amount of CO2 fixing to853.34 mg/L in the presence of MED. NO2-and S2O32-may play the roles of both electron acceptor and electron donor under aerobic conditions,which may improve the energy utilization efficiency of NPMC and enhance the CO2 fixation efficiency. The sequence determination of 16 S ribosomal deoxyribonucleic acid（rDNA） from 150 bacteria of NPMC showed that more than 50% of the bacteria were symbiotic and there were many heterotrophic bacteria such as Vibrio natriegens. These results indicate that NPMC acts as a symbiotic CO2 fixing system. The interaction between autotrophic and heterotrophic bacteria may be a crucial factor supporting ladder utilization and recycling of energy/carbon source.

Photocatalytic reduction of carbon dioxide by titanium oxide- based semiconductors to produce fuels

To tackle the crisis of global warming, it is imperative to control and mitigate the atmospheric carbon dioxide level. Photocatalytic reduction of carbon dioxide into solar fuels furnishes a gratifying solution to utilize and reduce carbon dioxide emission and simultaneously generate renewable energy to sustain the societies. So far, titanium oxide-based semiconductors have been the most prevalently adopted catalysts in carbon dioxide photoreduction. This mini-review provides a general summary of the recent progresses in titanium oxide- catalyzed photocatalytic reduction of carbon dioxide. It first illustrates the use of structural engineering as a strategy to adjust and improve the catalytic performances. Then, it describes the introduction of one/two exogenous elements to modify the photocatalytic activity and/or selectivity. Lastly, it discusses multi-component hybrid titanium oxide composites.

Enhanced photocatalytic CO_(2) hydrogenation with wide-spectrum utilization over black TiO_(2) supported catalyst

Light-driven conversion of CO_(2)into chemicals/fuels is a desirable approach for achieving carbon neutral-ity using clean and sustainable energy.However,its scale-up application is restricted due to insufficient efficiency.Herein,we present a photothermal catalytic hydrogenation of CO_(2)into CH_(4)over Ru/black TiO_(2) catalysts,aiming to achieve the synergistic use of light and heat in solar energy during CO_(2)conversion.Owing to the desirable spectral response ability and photothermal conversion performance of black TiO_(2),an efficient combination of photocatalysis and thermocatalysis has been established.The CO_(2)hydrogena-tion was significantly accelerated because of the increased catalyst surface temperature enabled by the photothermal effect of black TiO_(2).Simultaneously,through the in situ X-ray photoelectron spectroscopy(XPS)observation,electron-rich Ru nanoparticles was achieved based on the photo-induced excitation,thereby providing more negative hydride to improve nucleophilic attack to the CO_(2),obtaining the CH_(4) yield of 93.8%.

Special column:solar energy conversion

It is a great challenge to meet the increasing energy requirement due to the increase of the population and the improvement of the living standard. As the largest single available source of clean energy, the sun deposits 120000 TW of radiation on the earth. The efficient use of solar energy would be a promising solution for the energy issue. Therefore, great efforts were made to develop solar technologies, such as solar cells, photocatalysis, photoelectrical catalysis, and photothermal devices. In this special column, six articles in solar energy conversion have been accepted for publication.