Photovoltaics are an important source of renewable energy, but due to the intermittent nature of insolation, solar cells usually need to be connected to rechargeable batteries, electrochemical capacitors or other energy storage devices, which adds to the complexity and cost of these systems. In this work, a cathode design for photo‐rechargeable zinc‐ion batteries (photo‐ZIBs) is reported, that is inherently capable of harvesting sunlight to recharge without the need for external solar cells. The proposed photocathodes, comprising a composite of vanadium dioxide nanorods and reduced graphene oxide, are engineered to provide the necessary charge separation and storage for photocharging under illumination. The photo‐ZIBs achieve capacities of ≈282 mAh g−1 in the dark and ≈315 mAh g−1 under illumination, at 200 mA g−1, demonstrating the use of light not only to charge the devices, but additionally to enhance their capacity. The photo‐ZIBs also demonstrate enhanced high‐rate capabilities under illumination, as well as a capacity retention of ≈90% over 1000 cycles. The proposed photo‐ZIBs are considered a promising new technology for addressing energy poverty, due to their high performance and inherent cost‐efficiency and safety.

Electrochemical energy storage devices that can harvest energy from the environment and store it are increasingly important to address both energy poverty in developing parts of the world, as well as powering off-grid autonomous devices. Currently, batteries or supercapacitors connected to solar cells are used for these applications, but these frequently suffer from voltage mismatches and inefficiencies in the device packaging. This paper presents an optically and electrochemically active electrode for photo-rechargeable zinc-ion capacitors using vanadium oxide nanofibers. These rely on photo-excited charge carrier separation to charge the capacitors without any external photovoltaic or electrical devices. We found that silver nanowires are better than carbon based conductive additives as they support photo-excited holes transport and provides light scattering centers that enhance visible light absorption. The proposed capacitors show a ~ 63% capacity increase under illumination, photo-recharge in 30 minutes and ~ 99% capacity retention over 4000 cycles.

Extrapolating the properties of individual CNTs into macro-scale CNT materials using a continuous and cost effective process offers enormous potential for a variety of applications.The floating catalyst chemical vapor deposition (FCCVD) method discussed in this paper bridges the gap between generating nano-and macro-scale CNT material and has already been adopted by industry for exploitation. A deep understanding of the phenomena occurring within the FCCVD reactor is thereby key to producing the desired CNT product and successfully scaling up the process further. This paper correlates information on decomposition of reactants, axial catalyst nanoparticle dynamics and the morphology of the resultant CNTs and shows how these are strongly related to the temperature and chemical availability within the reactor. For the first time, in-situ measurements of catalyst particle size distributions coupled with reactant decomposition profiles and a detailed axial SEM study of formed CNT materials reveal specific domains that have important implications for scale-up.A novel observation is the formation, disappearance and reformation of catalyst nanoparticles along the reactor axis, caused by their evaporation and re-condensation and mapping of different CNT morphologies as a result of this process.

Aircraft black carbon (BC) emissions contribute to climate forcing, but few estimates of BC emitted by aircraft at cruise exist. For the majority of aircraft engines the only BC-related measurement available is smoke number (SN)-a filter based optical method designed to measure near-ground plume visibility, not mass. While the first order approximation (FOA3) technique has been developed to estimate BC mass emissions normalized by fuel burn [EI(BC)] from SN, it is shown that it underestimates EI(BC) by >90% in 35% of directly measured cases (R(2) = -0.10). As there are no plans to measure BC emissions from all existing certified engines-which will be in service for several decades-it is necessary to estimate EI(BC) for existing aircraft on the ground and at cruise. An alternative method, called FOX, that is independent of the SN is developed to estimate BC emissions. Estimates of EI(BC) at ground level are significantly improved (R(2) = 0.68), whereas estimates at cruise are within 30% of measurements. Implementing this approach for global civil aviation estimated aircraft BC emissions are revised upward by a factor of ~3. Direct radiative forcing (RF) due to aviation BC emissions is estimated to be ~9.5 mW/m(2), equivalent to ~1/3 of the current RF due to aviation CO2 emissions.

A techno-economic analysis of the environmental and economic feasibility of middle distillate fuel productionviafermentation and advanced fermentation technologies.