Supported manganese oxide catalysts were prepared by incipient wetness impregnation method for methane catalytic combustion, and effects of the support （Al2O3, SiO2 and TiO2） and Mn loading were ...investigated. These catalysts were characterized with N2 adsorption, X-ray diffraction, X-ray photoelectron spectroscopy and temperature-programmed reduction techniques. Methane conversion varied in a large range depending on supports or Mn loading. Al2O3 supported 15% Mn catalyst exhibited better activity toward methane catalytic oxidation. The manganese state and oxygen species played an important role in the catalytic performance,
High-voltage high-nickel lithium layered oxide cathodes show great application prospects to meet the ever-increasing demand for further improvement of the energy density of rechargeable lithium-ion ...batteries (LIBs) mainly due to their high output capacity. However, severe bulk structural degradation and undesired electrode-electrolyte interface reactions seriously endanger the cycle life and safety of the battery. Here, 2 mol% Ti atom is used as modified material doping into LiNi
0.6
Co
0.2
Mn
0.2
O
2
(NCM) to reform LiNi
0.6
Co
0.2
Mn
0.18
Ti
0.02
O
2
(NCM-Ti) and address the long-standing inherent problem. At a high cut-off voltage of 4.5 V, NCM-Ti delivers a higher capacity retention ratio (91.8% vs. 82.9%) after 150 cycles and a superior rate capacity (118 vs. 105 mAh·g-1) at the high current density of 10 C than the pristine NCM. The designed high-voltage full battery with graphite as anode and NCM-Ti as cathode also exhibits high energy density (240 Wh·kg-1) and excellent electrochemical performance. The superior electrochemical behavior can be attributed to the improved stability of the bulk structure and the electrode-electrolyte interface owing to the strong Ti-O bond and no unpaired electrons. The
in-situ
X-ray diffraction analysis demonstrates that Ti-doping inhibits the undesired H2-H3 phase transition, minimizing the mechanical degradation. The
ex-situ
TEM and X-ray photoelectron spectroscopy reveal that Ti-doping suppresses the release of interfacial oxygen, reducing undesired interfacial reactions. This work provides a valuable strategic guideline for the application of high-voltage high-nickel cathodes in LIBs.
This paper investigates the driving forces, emission trends and reduction potential of China's carbon dioxide (CO2) emissions based on a provincial panel data set covering the years 1995 to 2009. A ...series of static and dynamic panel data models are estimated, and then an optimal forecasting model selected by out-of-sample criteria is used to forecast the emission trend and reduction potential up to 2020. The estimation results show that economic development, technology progress and industry structure are the most important factors affecting China's CO2 emissions, while the impacts of energy consumption structure, trade openness and urbanization level are negligible. The inverted U-shaped relationship between per capita CO2 emissions and economic development level is not strongly supported by the estimation results. The impact of capital adjustment speed is significant. Scenario simulations further show that per capita and aggregate CO2 emissions of China will increase continuously up to 2020 under any of the three scenarios developed in this study, but the reduction potential is large.
► We construct a provincial panel of China’s CO2 emissions covering the year 1995–2009. ► We investigate driving forces and reduction potential of China’s CO2 emissions. ► The Environmental Kuznets Curve is not strongly supported by the estimation results. ► China’s CO2 emissions will increase up to 2020, but the reduction potential is large.
2D hierarchically porous carbon (2D-HPC) nanosheets with unique advantages are highly desired as host materials for lithium sulfur (Li–S) batteries and other energy storage devices. Herein, we ...propose a self-template and organic solvent-free approach to synthesize nanosheets of monoclinic ZIF-8 at room temperature from which 2D-HPC nanosheets (ZIF-8 nanosheets carbon denoted as ZIF-8-NS-C) are derived to be an efficient sulfur immobilizer for Li–S batteries for the first time. The anisotropic nanosheets are believed to relate to the symmetry of the monoclinic structure. The 2D ZIF-8-NS-C nanosheets with embedded hierarchical pores construct an effective conductive network through “plane-to-plane” modes to endow superior electron transfer and fast electrochemical kinetics. Moreover, the nitrogen-rich feature of ZIF-8-NS-C can increase the affinity/interaction of carbon host with lithium polysulfides, favoring the cyclic performance. The sulfur/ZIF-8-NS-C (S/ZIF-8-NS-C) cathode shows a superior rate capability with high capacities of 1226 mA h g–1 at 0.2 C and 785 mA h g–1 at 2 C, and a sustainable cycling stability with a capacity attenuation of 0.12% per cycle at 0.5 C for 300 cycles. The approach proposed here pioneers the controllable design of MOF-based structures to inspire the exploration of more variable MOF-derived porous materials for energy storage applications.
This paper aims to identify which provinces will be allocated more (less) of a carbon dioxide reduction burden within China's pledge to reduce its carbon intensity at the Copenhagen conference. Using ...an extended Slacks-Based Measure (SBM) model incorporating an undesirable output, the CO2 reduction potential and marginal abatement costs are estimated for 29 provinces over the period 1995–2007. The CO2 Abatement Capacity Index (ACI) is constructed based on weighted equity and efficiency indexes. We find that there exists a large gap in potential reduction capability and marginal abatement cost among the eastern, middle and western regions. The eastern region has the least inefficient emission and the highest marginal abatement cost, while the western region has the largest potential reduction capability and the lowest marginal cost faced in reducing CO2 emissions. The difference in potential CO2 abatement among the provinces results from different industry structures, energy compositions and degrees of the openness of trade. The ACI ranking and the final allocation among provinces depend on the policy-makers' preferences regarding equity and efficiency.
► 41% of China's CO2 are inefficient excessive emissions. ► Industry composition, energy mix, openness degree affect CO2 abatement potential. ► East has highest marginal cost and least abatement potential, vice versa of West. ► Allocation depends on policy-maker' choice between equity and efficiency.
This paper estimates the Marginal Abatement Cost Curve (MACC) of CO2 emissions in China based on a provincial panel for the period of 2001–2010. The provincial marginal abatement cost (MAC) of CO2 ...emissions is estimated using a parameterized directional output distance function. Four types of model specifications are applied to fit the MAC-carbon intensity pairs. The optimal specification controlling for various covariates is identified econometrically. A scenario simulation of China's 40–45% carbon intensity reduction based on our MACC is illustrated. Our simulation results show that China would incur a 559–623Yuan/t (roughly 51–57%) increase in marginal abatement cost to achieve a corresponding 40–45% reduction in carbon intensity compared to its 2005 level.
•Marginal Abatement Cost Curve of CO2 emissions in China is constructed.•The optimal specification is identified to fit the MAC-carbon intensity pairs.•An application of China's carbon intensity reduction goal is illustrated.
The applications of lanthanide-doped upconversion nanomaterials are limited by unsatisfactory brightness currently. Herein, a general strategy is proposed for boosting the upconversion efficiency in ...Er
ions, based on combined use of a core-shell nanostructured host and an integrated optical waveguide circuit excitation platform. A NaErF
@NaYF
core-shell nanoparticle is constructed to host the upconversion process for minimizing non-radiative dissipation of excitation energy by surface quenchers. Furthermore, an integrated optical microring resonator is designed to promote absorption of excitation light by the nanoparticles, which alleviates quenching of excited states due to cross-relaxation and phonon-assisted energy transfer. As a result, multiphoton upconversion emission with a large anti-Stokes shift (greater than 1150 nm) and a high energy conversion efficiency (over 5.0%) is achieved under excitation at 1550 nm. These advances in controlling photon upconversion offer exciting opportunities for important photonics applications.
In this paper, bismuth-rich three-dimensional Bi4O5I2/BiOBr hollow flower spheres were prepared by a one-pot solvothermal method. The anionic contaminant Rhodamine B (RhB) was used as the ...photocatalytic test contaminant. The results showed that the degradation rate of RhB was more than 99 %. Then Br element was introduced into Bi4O5I2 hollow flower balls, the diameter of flower balls decreased and flowers sparsely. With the increase of Br content, flower balls gradually increased in volume and became denser. Small and sparse flower balls increase the specific surface area of flower balls and increase the number of active sites, thus improving the REDOX capacity of photogenerated electrons and holes. Our findings suggest that both holes (h+) and superoxide radical anions (•O2−) are crucial players during photocatalysis. The aim of this study is to develop an efficient photocatalyst for the degradation of organic pollutants, and its photocatalytic mechanism is described theoretically.
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•Innovative synthesis methodology: An efficacious one-pot solvothermal method yielded a bismuth-rich three-dimensional Bi4O5I2/BiOBr hollow flower bulb framework, enhancing the material's specific surface area and providing more reactive sites for photocatalysis.•Energy band structure optimization: Incorporation of Br element modifies the Bi4O5I2 energy band structure into a type II heterojunction, promoting efficient electron-hole separation and enhancing photocatalytic efficiency.•Proposed photocatalytic mechanism: A plausible photocatalytic mechanism was proposed, elucidating the pivotal role of h+ and .•O2− in the photocatalytic process, and constructing a theoretical model based on experimental findings.
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