Applications In Energy Science Research Articles

Droplet-enabled controllable manipulation of tribo-charges from liquid-solid interface

Efficient utilization of electrostatic charges is paramount for numerous applications, from printing to kinetic energy harvesting. However, existing technologies predominantly focus on the static qualities of these charges, neglecting their dynamic capabilities as carriers for energy conversion. Herein, we report a paradigm-shifting strategy that orchestrates the swift transit of surface charges, generated through contact electrification, via a freely moving droplet. This technique ingeniously creates a besptengngoke charged surface which, in tandem with a droplet acting as a transfer medium to the ground, facilitates targeted charge displacement and amplifies electrical energy collection. The spontaneously generated electric field between the charged surface and needle tip, along with the enhanced water ionization under the electric field, proves pivotal in facilitating controlled charge transfer. By coupling the effects of charge self-transfer, contact electrification, and electrostatic induction, a dual-electrode droplet-driven triboelectric nanogenerator (DD–TENG) is designed to harvest the water-related energy, exhibiting a two-order-of-magnitude improvement in electrical output compared to traditional single-electrode systems. Our strategy establishes a fundamental groundwork for efficient water drop energy acquisition, offering deep insights and substantial utility for future interdisciplinary research and applications in energy science.

Elucidating the impact of ultrasonic treatment on bituminous oil properties: A comprehensive study of viscosity modification

As global energy needs rise and traditional oil production wanes, heavy and viscous oils are becoming increasingly important. This study explores the use of ultrasonic technology to reduce oil viscosity. We investigated the relationship between ultrasonic exposure duration and changes in bituminous oil composition, using chromatography-mass spectrometry to analyze chemical alterations in oil samples pre and post-ultrasonic treatment. Viscosity changes at varied temperatures and shear rates were measured using a vibration viscometer and a rheometer. Our results showed that the viscosity reduction ratio (VRR) peaked at over 30% after 3 min of ultrasonic exposure. However, some processing methods and oil compositions led to increased viscosity. Post-treatment, lighter oil components were more prevalent, suggesting that ultrasonic exposure disrupts long carbon chains, reducing viscosity. Conversely, viscosity increases may result from molecular reconnection within bituminous oil. This research provides insights into a novel method for reducing heavy oil viscosity using ultrasonic technology, broadening our understanding of its applications in energy science and highlighting its potential to revolutionize heavy oil utilization.

Piezovoltaics from PdHx

Metal hydrides have wide applications in energy science. A large pressure gradient propels the hydrogen atoms out. A piezovoltaic device, a pressure gradient-driven battery, can therefore be realized when the migrations of protons and electrons are separated by different conductors. Here we investigate the piezovoltaic performance of PdHx with various proton conductors as electrolytes and experimentally detect an output current of ≲40 nA and a voltage of ∼0.8 V for a 3 μg sample. We also demonstrate the escape of hydrogen atoms from a palladium lattice under an increasing pressure gradient using X-ray diffraction. The relationship between piezovoltaics (chemical process) and piezoelectricity (physical process) is like that between a chemical battery and a capacitor. Our work demonstrates the piezovoltaic application of metal hydrides and provides a new way to convert mechanical energy into electrical energy.

Controllable Frequency Dependence of Resonance Energy Transfer Coupled with Localized Surface Plasmon Polaritons.

We investigate the intrinsic characteristics of resonance energy transfer (RET) coupled with localized surface plasmon polaritons (LSPPs) from the perspective of macroscopic quantum electrodynamics. To quantify the effect of LSPPs, we propose a numerical scheme that allows us to accurately calculate the rate of RET between a donor-acceptor pair near a nanoparticle. Our study shows that LSPPs can be used to enhance the RET rate significantly and control its frequency dependence by modifying a core/shell structure, which indicates the possibility of RET rate optimization. Moreover, we systematically explore the angle (distance) dependence of the RET rate and analyze its origin. According to different frequency regimes, the angle dependence of RET is dominated by different mechanisms, such as LSPPs, surface plasmon polaritons (SPPs), and anti-resonance. For the proposed core/shell structure, the characteristic distance of RET coupled with LSPPs (approximately 0.05 emission wavelength) is shorter than that of RET coupled with SPPs (approximately 0.1 emission wavelength), which may provide promising applications in energy science.

On the first principle theory of nanogenerators from Maxwell's equations

Nanogenerators (NGs) are a field that uses Maxwell's displacement current as the driving force for effectively converting mechanical energy into electric power/signal, which have broad applications in energy science, environmental protection, wearable electronics, self-powered sensors, medical science, robotics and artificial intelligence. NGs are usually based on three effects: piezoelectricity, triboelectricity (contact electrification), and pyroelectricity. In this paper, a formal theory for NGs is presented starting from Maxwell's equations. Besides the general expression for displacement vector D = εE used for deriving classical electromagnetic dynamics, we added an additional term Ps in D, which represents the polarization created by the electrostatic surface charges owing to piezoelectricity and/or triboelectricity as a result of mechanical triggering in NG. In contrast to P that is resulted from the electric field induced medium polarization and vanishes if E = 0, Ps remains even when there is no external electric field. We reformulated the Maxwell equations that include both the medium polarizations due to electric field (P) and non-electric field (such as strain) (Ps) induced polarization terms, from which, the output power, electromagnetic behavior and current transport equation for a NG are systematically derived. A general solution is presented for the modified Maxwell equations, and analytical solutions about the output potential are provided for a few cases. The displacement current arising from ε∂E/∂t is responsible for the electromagnetic waves, while the newly added term ∂Ps/∂t is the application of Maxwell's equations in energy and sensors. This work sets the first principle theory for quantifying the performance and electromagnetic behavior of a nanogenerator in general.

Evidence for an Electronic State at the Interface between the SnO2 Core and the TiO2 Shell in Mesoporous SnO2/TiO2 Thin Films

A comparative spectroelectrochemical study of micron thick mesoporous thin films composed of TiO2 and SnO2 nanocrystallites was undertaken to identify the location and identity of electronic state(s) in core/shell SnO2/TiO2 films that have emerging applications in energy science. The mesoporous TiO2 and SnO2 films were synthesized by sol–gel techniques, and the core/shell material was created by atomic layer deposition of a TiO2 shell on a SnO2 core. Electrochemical reduction of these materials in aqueous electrolytes resulted in a blue shift of the fundamental VB → CB absorbance as well as a broad absorbance across the visible region. For SnO2, three unique spectra were required to model the potential dependent data while only one unique spectrum was needed to model the corresponding data for SnO2/TiO2 and TiO2. Significantly, standard addition of the spectra measured for SnO2 and TiO2 did not model that for SnO2/TiO2. In other words, upon reduction of SnO2/TiO2 there was no spectroscopic evidence for el...

Peroxidase-Enhanced Photocatalytic Activity of Au-Cu2O Core-Shell Nanocrystals

As the talented motif of two-component systems, core-shell nanocrystals with multi-functional chemical properties have attracted ever-increasing interests. Among the different material combinations, Au-based core-shell nanocrystals are particularly appealing since the protected, nano-sized Au can perform a myriad of catalytic reactions, e.g. peroxidase enzyme mimics. On the other hand, utilization of Au can benefit semiconductor nanostructures for various photocatalytic applications. The introduced Au may function as charge separation enhancer for semiconductor, which improves the carrier utilization efficiency to promote photocatalysis. In this work, Au-Cu2O core-shell nanocrystals were synthesized and used for unique peroxidase-assisted photocatalytic applications. By virtue of the peroxidase-like property of nano-sized Au, Au-Cu2O can catalyze hydrogen peroxide to generate OH radicals for participation in photocatalytic reactions. On the other hand, due to the relative band alignment, introduction of Au can enhance the charge separation of Cu2O, therefore improving the overall photocatalytic activity. The peroxidase-enhanced photocatalytic properties of Au-Cu2O nanocrystals were evaluated by using methyl orange as the test pollutant. The results showed that Au-Cu2O surpassed pure Au and pure Cu2O in methyl orange degradation under light illumination. This superiority was ascribed to the functionality synergy between the remarkable peroxidase activity of Au and the pronounced charge separation of Au-Cu2O. This work delivers a new photocatalyst configuration by exploiting the multi-functionalities of nanosized Au for environmental and energy science applications.

Particle accelerator physics and technology for high energy density physics research

Interaction phenomena of intense ion- and laser radiation with matter have a large range of application in different fields of science, extending from basic research of plasma properties to applications in energy science, especially in inertial fusion. The heavy ion synchrotron at GSI now routinely delivers intense uranium beams that deposit about 1 kJ/g of specific energy in solid matter, e.g. solid lead. Our simulations show that the new accelerator complex FAIR (Facility for Antiproton and Ion Research) at GSI as well as beams from the CERN large hadron collider (LHC) will vastly extend the accessible parameter range for high energy density states. A natural example of hot dense plasma is provided by our neighbouring star the sun, and allows a deep insight into the physics of fusion, the properties of matter at high energy density, and is moreover an excellent laboratory for astroparticle physics. As such the sun's interior plasma can even be used to probe the existence of novel particles and dark matter candidates. We present an overview on recent results and developments of dense plasma physics addressed with heavy ion and laser beams combined with accelerator- and nuclear physics technology.