Nano-enhanced solid-state hydrogen storage:Balancing discovery and pragmatism for future energy solutions

Nanomaterials have revolutionized the battery industry by enhancing energy storage capacities and charging speeds,and their application in hydrogen(H_(2))storage likewise holds strong potential,though with distinct challenges and mechanisms.H_(2) is a crucial future zero-carbon energy vector given its high gravimetric energy density,which far exceeds that of liquid hydrocarbons.However,its low volumetric energy density in gaseous form currently requires storage under high pressure or at low temperature.This review critically examines the current and prospective landscapes of solid-state H_(2) storage technologies,with a focus on pragmatic integration of advanced materials such as metal-organic frameworks(MOFs),magnesium-based hybrids,and novel sorbents into future energy networks.These materials,enhanced by nanotechnology,could significantly improve the efficiency and capacity of H_(2) storage systems by optimizing H_(2) adsorption at the nanoscale and improving the kinetics of H_(2) uptake and release.We discuss various H_(2) storage mechanisms—physisorption,chemisorption,and the Kubas interaction—analyzing their impact on the energy efficiency and scalability of storage solutions.The review also addresses the potential of“smart MOFs”,single-atom catalyst-doped metal hydrides,MXenes and entropy-driven alloys to enhance the performance and broaden the application range of H_(2) storage systems,stressing the need for innovative materials and system integration to satisfy future energy demands.High-throughput screening,combined with machine learning algorithms,is noted as a promising approach to identify patterns and predict the behavior of novel materials under various conditions,significantly reducing the time and cost associated with experimental trials.In closing,we discuss the increasing involvement of various companies in solid-state H_(2) storage,particularly in prototype vehicles,from a techno-economic perspective.This forward-looking perspective underscores the necessity for ongoing material innovation and system optimization to meet the stringent energy demands and ambitious sustainability targets increasingly in demand.

Synthesis of new two-dimensional titanium carbonitride Ti_(2)C_(0.5)N_(0.5)T_(x)MXene and its performance as an electrode material for sodium-ion battery

Two-dimensional(2D)layered transition metal carbides/nitrides,called MXenes,are attractive alternative electrode materials for electrochemical energy storage.Owing to their metallic electrical conductivity and low ion dif-fusion barrier,MXenes are promising anode materials for sodium-ion batteries(SIBs).Herein,we report on a new 2D carbonitride MXene,viz.,Ti_(2)C_(0.5)N_(0.5)T_(x)(T_(x) stands for surface terminations),and the only second carbonitride after Ti_(3) CNT_(x) so far.A new type of in situ HF(HCl/KF)etching condition was employed to synthesize multilayer Ti_(2)C_(0.5)N_(0.5)T_(x) powders from Ti_(2)AlC_(0.5)N_(0.5).Spontaneous intercalation of tetramethylammonium followed by sonication in water allowed for large-scale delamination of this new titanium carbonitride into 2D sheets.Multilayer Ti_(2)C_(0.5)N_(0.5)T_(x) powders showed higher specific capac-ities and larger electroactive surface area than those of Ti_(2)CT_(x) powders.Multi-layer Ti_(2)C_(0.5)N_(0.5)T_(x) powders show a specific capacity of 182 mAh g^(-1) at 20 mA g^(-1),the highest among all reported MXene electrodes as SIBs with excellent cycling stability.

Tailoring spin mixtures by ion-enhanced Maxwell magnetic coupling in colortunable organic electroluminescent devices

In this work,we show that the spin dynamics of excitons can be dramatically altered by Maxwell magnetic field coupling,together with an ion-enhanced,low-internal-splitting-energy organic semiconducting emitter.By employing a unique,alternating current(AC)-driven organic electroluminescent(OEL)device architecture that optimizes this magnetic field coupling,almost complete control over the singlet-to-triplet ratio(from fluorescent to phosphorescent emission in a single device)is realized.We attribute this spin population control to magnetically sensitive polaron–spin pair intersystem crossings(ISCs)that can be directly manipulated through external driving conditions.As an illustration of the utility of this approach to spin-tailoring,we demonstrate a simple hybrid(double-layer)fluorescence–phosphorescence(F–P)device using a polyfluorene-based emitter with a strong external Zeeman effect and ion-induced long carrier diffusion.Remarkable control over de-excitation pathways is achieved by controlling the device-driving frequency,resulting in complete emission blue–red color tunability.Picosecond photoluminescence(PL)spectroscopy directly confirms that this color control derives from the magnetic manipulation of the singlet-totriplet ratios.These results may pave the way to far more exotic organic devices with magnetic-field-coupled organic systems that are poised to usher in an era of dynamic spintronics at room temperature.

Selective Pb^(2+) removal and electrochemical regeneration of fresh and recycled FeOOH

Heavy metal pollution is a key environmental problem.Selectively extracting heavy metals could accomplish water purification and resource recycling simultaneously.Adsorption is a promising approach with a facile process,adaptability for the broad concentration of feed water,and high selectivity.However,the adsorption method faces challenges in synthesizing highperformance sorbents and regenerating adsorbents effectively.FeOOH is an environmentally friendly sorbent with low-cost production on a large scale.Nevertheless,the selectivity behavior and regeneration of FeOOH are seldom studied.Therefore,we investigated the selectivity of FeOOH in a mixed solution of Co^(2+),Ni^(2+),and Pb^(2+)and proposed to enhance the capacity of FeOOH and regenerate it by using external charges.Without charge,the FeOOH electrode shows a Pb^(2+)uptake capacity of 20 mg/g.After applying a voltage of-0.2/+0.8 V,the uptake capacity increases to a maximum of 42 mg/g and the desorption ratio is 70%-80%.In 35 cycles,FeOOH shows a superior selectivity towards Pb^(2+)compared with Co^(2+)and Ni^(2+),with a purity of 97%±3%in the extracts.The high selectivity is attributed to the lower activation energy for Pb^(2+)sorption.The capacity retentions at the 5^(th)and the 35^(th)cycles are ca.80%and ca.50%,respectively,comparable to the chemical regeneration method.With industrially exhausted granular ferric hydroxide as the electrode material,the system exhibits a Pb^(2+)uptake capacity of 37.4 mg/g with high selectivity.Our work demonstrates the feasibility of regenerating FeOOH by charge and provides a new approach for recycling and upcycling FeOOH sorbent.