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The catalytic active sites of NiFe and NiFeCr (oxy)hydroxides are revealed byoperandospectroscopic techonologies for alkaline water oxidation.

AbstractHigh‐performance dye‐sensitized solar cell (DSSC) devices rely on photoanodes that possess excellent light‐harvesting capabilities and high surface areas for sufficient dye adsorption. In this work, morphologically controlled SnO2 microstructures were synthesized and used as an efficient light‐backscattering layer on top of a nanocrystalline TiO2 layer to prepare a double‐layered photoanode. By optimizing the thickness of both the TiO2 bottom layer and the SnO2 top layer, a high power conversion efficiency (PCE) of 7.8 % was achieved, an enhancement of approximately 38 % in the efficiency compared with that of a nanocrystalline TiO2‐only photoanode (5.6 %). We attribute this efficiency improvement to the superior light‐backscattering capability of the SnO2 microstructures.

Energy mix persistence is a defining characteristic of energy systems, for reasons including the long‐lived nature of energy infrastructure and the role of local endowments. This persistence is evident in current energy‐type use being strongly influenced by past use. Our analysis uses data for eight energy types and a large sample of countries, finding varying degrees of energy mix persistence. We also find evidence that carbon pricing appears to have played a key role in tilting energy mixes from coal towards renewable energy. Our estimates provide empirical support to policymakers seeking to implement carbon pricing to transition their energy systems in a lower‐carbon direction.

Abstract We evaluated three Integrated Assessment Models (IAMs: IGSM, MERGE, MiniCAM) by: (i) comparing their global Primary Energy year-2000 initializations and projections for 2010 and 2015 to historical data; (ii) mapping their CO2 emissions projections against observations; and (iii) examining model-output diagnostics. The IAMs underestimated historical primary energy consumption and initial/projected CO2 emissions in both reference and stabilization scenarios (particularly for combustion fuels) but overestimated usage of non-biomass renewables, causing underestimates of future CO2 emissions that, for the stabilization scenarios, are wildly optimistic. Mitigation technology breakdowns in the policy scenarios vary enormously across IAMs, suggesting that confidence in their projections might be misplaced, or that options for mitigation have greater scope than is supposed. Most increases in carbon-free technologies in the stabilization scenarios are already captured in the reference cases. Energy-conversion efficiencies in electricity generation improve over time, but, (except for gas-powered generation in IGSM), efficiencies in the policy scenarios are less than in the reference. Electrification results diverge widely: IGSM has little change over the 21st century, while MiniCAM and MERGE have major electrification increases in their policy scenarios. We suggest: 1) comprehensive model output suitable for secondary analysis should be more readily available; 2) directly comparable reference and policy-driven mitigation scenarios are essential for assessing mitigation measures; 3) model validation using historical, source-specific energy data is crucial for assessing model credibility; 4) separation of mitigation contributions into no-policy and policy-driven amounts is needed to assess the effectiveness of mitigation policies; and 5) detailed inter-model comparisons can provide important insights into model credibility.

AbstractMultinational conservation initiatives that prioritize investment across a region invariably navigate trade-offs among multiple objectives. It seems logical to focus where several objectives can be achieved efficiently, but such multi-objective hotspots may be ecologically inappropriate, or politically inequitable. Here we devise a framework to facilitate a regionally cohesive set of marine-protected areas driven by national preferences and supported by quantitative conservation prioritization analyses, and illustrate it using the Coral Triangle Initiative. We identify areas important for achieving six objectives to address ecosystem representation, threatened fauna, connectivity and climate change. We expose trade-offs between areas that contribute substantially to several objectives and those meeting one or two objectives extremely well. Hence there are two strategies to guide countries choosing to implement regional goals nationally: multi-objective hotspots and complementary sets of single-objective priorities. This novel framework is applicable to any multilateral or global initiative seeking to apply quantitative information in decision making.

Rechargeable aluminum batteries (AlBs), which represent cost‐effective energy‐storage devices due to the abundance of natural aluminum resources, have emerged as promising candidates for the next generation of rechargeable batteries. Although the electrochemical deposition of aluminum in ionic liquids (ILs) is well investigated for aluminum refining, the reversible electrochemical deposition/dissolution behavior of aluminum ions is not trivial. More specifically, the dendrite growth issue, which is common in Li metal anodes, is scarcer or vague. Herein, the electrochemical stability of the aluminum metal anode in IL electrolytes is investigated and the failure mechanism is discussed. It is confirmed that the inorganic anion of ILs mainly affects the electrochemical stability, whereas the organic cation influences the aluminum metal degradation. X‐ray computed tomography results further identify deterioration of the surface morphology of the aluminum metal. The formation of “dead aluminum” is further confirmed, which indeed causes cell failure with repeated cycles. Finally, using the predeposited aluminum graphene paper as an alternative anode candidate for AlBs is further demonstrated.

Abstract This study aims to gain insight into the mechanism and kinetics during the gasification of biochar in steam, which was formed in situ in a fluidised-bed reactor using mallee wood in two particle size ranges of 0.80–1.0 mm and 2.0–3.3 mm. The overall biochar gasification rate and the formation rates of key product components were calculated by continuously monitoring the product gas stream with a quadrupole mass spectrometer. The kinetic compensation effects reveal that CO and CO2 are both formed from the heterogeneous reactions between the biochar surface and H2O. CO2 is formed either by the surface (biochar)-catalysed water-gas-shift reaction or directly from the carbon active sites involving the same intermediate for the formation of CO, as revealed by the apparent activation energies and apparent pre-exponential factors for CO and CO2 formation. The changes in the particle size of biomass substrate do not affect the extent of the kinetic compensation effects of biochar consumption and formation of CO, CO2 and H2 in the kinetics-controlled and mixed regimes. The similar extent of the kinetic compensation effects of H2 formation and biochar consumption for both particle sizes indicates that the formation of H2 also mainly involve the carbon active sites on the biochar surface instead of the gas-phase water-gas-shift reaction.

Abstract This review article aims to provide a comprehensive understanding of radiative cooling technology and their applications, especially on the integration of radiative coolers with devices. Over the past decades, radiative coolers and their applications have been intensively investigated because of their outstanding features for energy saving. The fundamental mechanism and characteristics of radiative cooling, in particular, atmospheric influences, and photothermal manipulation through structural and materials engineering, play essential roles in most of the practical applications. In general, these main factors concomitantly influence the cooling performance of a radiative cooler. However, comprehensive review investigating these main parameters simultaneously remains elusive. In this article, the fundamental features of radiative coolers are discussed, especially the influences of atmospheric conditions at different locations on the radiative coolers, and the photothermal manipulation capability and cooling performance of different types of radiative coolers. The applications, challenges faced in this field and the future trends are also discussed. This article will provide guidance towards integration of radiative coolers with functional devices for both academic researchers and engineers in the fields of energy harvesting, fluidic cooling, energy efficient clothing, and architecture.