Abstract
Designing catalytic materials with enhanced stability and activity is crucial for sustainable electrochemical energy technologies. RuO
2
is the most active material for oxygen evolution ...reaction (OER) in electrolysers aiming at producing ‘green’ hydrogen, however it encounters critical electrochemical oxidation and dissolution issues during reaction. It remains a grand challenge to achieve stable and active RuO
2
electrocatalyst as the current strategies usually enhance one of the two properties at the expense of the other. Here, we report breaking the stability and activity limits of RuO
2
in neutral and alkaline environments by constructing a RuO
2
/CoO
x
interface. We demonstrate that RuO
2
can be greatly stabilized on the CoO
x
substrate to exceed the Pourbaix stability limit of bulk RuO
2
. This is realized by the preferential oxidation of CoO
x
during OER and the electron gain of RuO
2
through the interface. Besides, a highly active Ru/Co dual-atom site can be generated around the RuO
2
/CoO
x
interface to synergistically adsorb the oxygen intermediates, leading to a favourable reaction path. The as-designed RuO
2
/CoO
x
catalyst provides an avenue to achieve stable and active materials for sustainable electrochemical energy technologies.
Anode-free batteries (AFBs) are impressive and recent phenomena in the era of energy storage devices due to their high energy density and relative ease of production compared to the traditional ...Lithium metal batteries (LMBs). However, dendrite formation during plating and stripping and low coulombic efficiency (CE) are the main challenges that impede practical implementation of these batteries. Here we report an extremely stable dual-salt electrolyte, 2M LiFSI+1M LiTFSI (2FSI+1TFSI)) in DME/DOL (1:1, v/v), system in comparison to the single salt 3M LiTFSI (3TFSI) in DME/DOL (1:1, v/v), to effectively stabilize AFB composed of LiFePO4 cathode and bare Cu-foil anode for the first time. The electrolyte stabilized anode-free cell with the configuration Cu||LiFePO4 via reductive decomposition of its anions and enabled the cell to be cycled with CE of 98.9% for 100 cycles. This results from the formation of stable, ion conductive and electrically insulating inorganic components rich Solid Electrolyte Interface (SEI) layer on the surface of in-situ deposited Li-metal that blocks the undesirable parasitic reaction between the deposited Li and the electrolyte. Thus, aforesaid SEI mitigates formation of dead lithium and dissolution of the in-situ deposited Li surface during repeated cycling and prolongs cycle life of the battery.
Atomically dispersed single-atom catalysts have the potential to bridge heterogeneous and homogeneous catalysis. Dozens of single-atom catalysts have been developed, and they exhibit notable ...catalytic activity and selectivity that are not achievable on metal surfaces. Although promising, there is limited knowledge about the boundaries for the monometallic single-atom phase space, not to mention multimetallic phase spaces. Here, single-atom catalysts based on 37 monometallic elements are synthesized using a dissolution-and-carbonization method, characterized and analysed to build the largest reported library of single-atom catalysts. In conjunction with in situ studies, we uncover unified principles on the oxidation state, coordination number, bond length, coordination element and metal loading of single atoms to guide the design of single-atom catalysts with atomically dispersed atoms anchored on N-doped carbon. We utilize the library to open up complex multimetallic phase spaces for single-atom catalysts and demonstrate that there is no fundamental limit on using single-atom anchor sites as structural units to assemble concentration-complex single-atom catalyst materials with up to 12 different elements. Our work offers a single-atom library spanning from monometallic to concentration-complex multimetallic materials for the rational design of single-atom catalysts.
Abstract
Imitating the natural photosynthesis to synthesize hydrocarbon fuels represents a viable strategy for solar-to-chemical energy conversion, where utilizing low-energy photons, especially ...near-infrared photons, has been the ultimate yet challenging aim to further improving conversion efficiency. Plasmonic metals have proven their ability in absorbing low-energy photons, however, it remains an obstacle in effectively coupling this energy into reactant molecules. Here we report the broadband plasmon-induced CO
2
reduction reaction with water, which achieves a CH
4
production rate of 0.55 mmol g
−1
h
−1
with 100% selectivity to hydrocarbon products under 400 mW cm
−2
full-spectrum light illumination and an apparent quantum efficiency of 0.38% at 800 nm illumination. We find that the enhanced local electric field plays an irreplaceable role in efficient multiphoton absorption and selective energy transfer for such an excellent light-driven catalytic performance. This work paves the way to the technique for low-energy photon utilization.
Fused Deposition Modeling (FDM) can be used to manufacture any complex geometry and internal structures, and it has been widely applied in many industries, such as the biomedical, manufacturing, ...aerospace, automobile, industrial, and building industries. The purpose of this research is to characterize the polylactic acid (PLA) and polyethylene terephthalate glycol (PETG) materials of FDM under four loading conditions (tension, compression, bending, and thermal deformation), in order to obtain data regarding different printing temperatures and speeds. The results indicated that PLA and PETG materials exhibit an obvious tensile and compression asymmetry. It was observed that the mechanical properties (tension, compression, and bending) of PLA and PETG are increased at higher printing temperatures, and that the effect of speed on PLA and PETG shows different results. In addition, the mechanical properties of PLA are greater than those of PETG, but the thermal deformation is the opposite. The above results will be a great help for researchers who are working with polymers and FDM technology to achieve sustainability.
It is essential to decouple the interfacial reactions taking place at the anode and cathode in rechargeable batteries. However, due to the reactive nature of Li, it is challenging to use Li‐metal ...batteries (LMBs) protocol to decouple the interfacial reactions. The by‐products from the anode or cathode become mixed in Li/NMC111 cells, which make decoupling interfacial reactions difficult. Here, reactions at electrodes are successfully decoupled and demystified using a protocol combining anode‐free LMB (AFLMB) with online electrochemical mass spectroscopy. LiPF6 in ethylene carbonate (EC)/diethyl carbonate (DEC) and EC/ethyl methyl carbonate (1:1 v/v%) electrolytes are used to compare interfacial reactions in Li/NMC111 and Cu/NMC111 cells. In Cu/NMC111, the evolution of CO2, CO, and C2H4 gases at the initial stage of first charging is due to interfacial reactions at Cu surface due to solid–electrolyte‐interphase formation. However, the evolution of CO2 and CO gases at high voltage in the entire cycles is associated with chemical and/or electrochemical electrolyte oxidation at the cathode. This work paves a new concept to decouple interfacial reactions at electrodes for developing electrochemically stable electrolytes to improve the performance with the long‐cycling life of AFLMBs and LMBs.
Reductive and oxidative gases evolving at the anode and cathode in Li/NMC111 and Cu/NMC111 are independently studied using a protocol combining EL‐Cell and GC‐MS. Understanding the decoupled interfacial reactions at both electrodes help elucidate the solid–electrolyte‐interphase formation mechanism and develop stable and high‐performance electrolytes.
Shifting from the typical 4e– pathway to H2O in electrochemical oxygen reduction to the 2e– pathway to H2O2 is increasingly recognized as an environmentally friendly approach for producing H2O2. ...However, the competitive 4e− pathway is a significant obstacle to the production of H2O2 since H2O is the thermodynamically favored product. Here, a series of Pt, Pd, and Rh active atoms diluted within inert‐Au matrices with precisely controlled atomic arrangements and coordination environments are synthesized via facet engineering for O2‐to‐H2O2 production. Surprisingly, individually dispersed Pt atoms within the Au surface enclosed by the square atomic arrangements exhibit superior H2O2 selectivity and achieve a maximum selectivity of 90% at 0.36 V versus the reversible hydrogen electrode. Operando synchrotron ambient pressure X‐ray photoelectron spectroscopy identifies the presence of *OOH key intermediates on these isolated Pt active sites. Grand canonical density‐functional theory also reveals that the kinetic energy barrier for the 2e− pathway (0.08 eV; OOH* + H+ + e− → H2O2) on the isolated Pt sites is significantly lower than the 4e− pathway (0.29 eV; OOH* + H+ + e− → O* + H2O). This work enables atomic‐scale control in dilute binary alloy surfaces with specific configurations of isolated active atoms and provides essential guidance for catalyst design to boost O2‐to‐H2O2 production.
Active Pt, Pd, and Rh atoms dispersed in inert‐Au matrices with controlled atomic arrangements and coordination environments are synthesized for electrocatalytic O2‐to‐H2O2 production. Surprisingly, isolated Pt atoms enclosed by square arrangements exhibit superior H2O2 selectivity of 90%. Operando X‐ray photoelectron spectroscopy and density‐functional theory uncover *OOH intermediates, highlighting a lower kinetic barrier of 0.08 eV for two‐electron oxygen reduction reaction.
We present evidence that the de‐trended, boreal winter sea surface temperature anomalies (SSTA) in the western North Pacific (WNP) are a skillful predictor for the development of the El Niño‐Southern ...Oscillation (ENSO) by the following winter. The WNP shares some similarities with the Meridional Mode (MM) located in the subtropical central and eastern North Pacific: both are linked to off‐equatorial SSTA and low‐level wind anomalies, and both appear to be strongly related to wintertime variability in the North Pacific Oscillation (NPO). However, in contrast with the MM, the WNP is associated with an opposite‐signed SSTA dipole located off southeastern Asia and in the western tropical Pacific, which is accompanied by equatorial winds that may influence the level of oceanic Kelvin wave activity that precedes ENSO events.
Key Points
Identification of the western North Pacific (WNP) region for SSTA
Winter SSTA in WNP is a skillful predictor for ENSO development
WNP SSTA initiates equatorial winds that influence oceanic Kelvin waves
Objective
Previous theoretical analysis predicted that phonation threshold flow (PTF) could be a more sensitive aerodynamic measure than phonation threshold pressure (PTP) for reflecting glottal ...incompetence. This study investigated the feasibility of whether PTP and PTF may differentiate subjects with unilateral adductor vocal fold paralysis and paresis (UAVFP) from those without, and whether PTP and PTF could reflect the extent of incomplete glottal closure associated with UAVFP.
Methods
PTP and PTF were quantified for 13 subjects with UAVFP and 21 control subjects with normal voice, and the normalized glottal gap area (NGGA) based on videostroboscopic image analysis was quantified for subjects with UAVFP.
Results
Significant differences in both PTP and PTF were found between subjects with UAVFP and control subjects. Receiver operating characteristic analysis indicated a higher discriminatory ability of PTP for differentiating subjects with UAVFP from those without (area under the curve of 0.905 for PTP, 0.678 for PTF), yet a significant positive correlation was found between PTF and NGGA (Spearman's ρ = 0.571) but not between PTP and NGGA (ρ = −0.364).
Conclusion
Results supported the feasibility of using PTP and PTF as potential diagnostic indicators for reflecting glottal closure in UAVFP, with PTP potentially more sensitive for differentiating subjects with and without incomplete glottal closure. These preliminary findings were limited by the small sample size, with further studies needed to verify whether PTF could be more sensitive for reflecting the extent of incomplete glottal closure, as predicted theoretically.
Level of Evidence
3 Laryngoscope, 131:E1598–E1604, 2021
PDF
