Lasers operating in the 2 µm spectral region have significant application value and development potential in fields such as lidar, medical surgery, and mid-infrared nonlinear optics because they are located in the atmospheric absorption window and coincide with a strong absorption peak of water molecules. This article first briefly introduces the energy level characteristics and commonly used crystal matrices of Tm3+, Ho3+ and Tm3+/Ho3+ codoped systems, and then reviews the research progress of 2 µm side-pumped solid-state lasers based on these ions and matrices. This review summarizes the research progress of 2 µm side-pumped solid-state lasers, categorized by operating mode and gain medium. Particular attention is given to the mature advantages of Tm-doped garnet lasers in high average power output and the potential of Tm/Ho-codoped fluoride lasers in high-energy, high-beam-quality pulse output. Finally, this paper further reviews the development of side-pumped laser structures and offers a prospective outlook on the future development of 2 µm region side-pumped lasers.

Electrocatalytic nitrogen reduction reaction (NRR) has emerged as a promising sustainable approach for ambient-condition ammonia synthesis. Extensive studies have identified Ti3+ as the predominant active site that facilitates NRR by lowering activation barriers and enhancing N2 chemisorption, which accounts for the remarkable catalytic performance of Ti2O3. The incorporation of molybdenum (Mo), a key component of nitrogenase active centers, has been shown to further improve NRR efficiency through its dual functionality in simultaneously activating and stabilizing the reaction intermediate. In this work, we report Mo-doped Ti2O3 nanoparticles that demonstrate superior NRR performance, achieving an ammonia yield of 30.84 μg h-1 mgcat-1 with a faradaic efficiency of 29.8%. These findings provide fundamental insights into the design principles of high-efficiency NRR catalysts and represent a significant advancement toward sustainable ammonia production technologies.

Transition-metal dichalcogenides (TMDs) have attracted considerable interest in ultrafast photonics. Among them, the emerging Dirac semimetal nickel ditelluride (NiTe2), with its broadband optical response and strong optical nonlinearity, is a promising material for saturable absorbers (SAs). However, its application in solid-state lasers remains largely unexplored. Here, we report the first use of a NiTe2-SA in a Tm-doped solid-state laser and demonstrate stable passive Q-switching. The NiTe2-SA was fabricated by liquid-phase exfoliation followed by spin coating, and its nonlinear transmission characteristics were investigated at 2 μm. Fitting of the saturable absorption curve yielded a modulation depth of 17.1% and a saturation intensity of 157.5 kW/cm^2. By incorporating the NiTe2-SA into a linear laser cavity, stable Q-switched pulses were generated at a central wavelength of 1985.9 nm. The pulse repetition rate reached 30.9kHz, while the shortest pulse duration and highestsingle-pulse energy were 2.3 μs and 13.0 μJ, respectively. During continuous operation overapproximately 2.48h, the average output power exhibited a fluctuation of only 2.53. These results highlight the potential of NiTe2 as a broadband SA for pulsed solid-state lasers, particularly in the 2 μm spectral region.

Hydrogenation of nitrogen-containing organic compounds (NOCs) are widely used in chemical industry, medicine and energy as an effective approach to achieving a sustainable artificial nitrogen cycle. Conventional fossil-fuel-driven thermochemical hydrogenation of high-pressure hydrogen is an energy-intensive carbon emission process. In contrast, aqueous electrochemical hydrogenation (ECH) offers a greener alternative by using water as a hydrogen source under ambient conditions, utilizing cathode potential instead of heat and hydrogen inputs. ECH of NOCs presents a potent method to convert renewable energy into value-added nitrogen-containing products under environmental conditions. However, challenges such as low conversion rates, competition from hydrogen evolution, and the complexity of the ECH process significantly impact the activity and conversion efficiency of hydrogenation catalysts, particularly reducing the selectivity for the target nitrogen-containing molecules. Investigating selective ECH can mitigate by-product and waste emissions associated with traditional chemical processes, advance green chemical technology, and expand the market for value-added nitrogen-containing organic products. This review summarizes the recent research progress on the selective ECH of representative NOCs, covering the underlying mechanisms and activity indicators related to proton activation on catalysts surface. Additionally, three strategies (structure/component optimization, interface engineering and reaction engineering) were proposed to enhance the selectivity of ECH to upgrade NOCs into nitrogen-containing organic value-added products, combined with in-situ characterization techniques for probing reaction intermediates and theoretical calculations to clarify structure-activity relationships. These approaches collectively enable the investigation and optimization of proton activation, electron transfer, and substrate hydrogenation pathways at the catalyst-electrolyte interface, aiming to upgrade NOCs into value-added products. characterization techniques for probing reaction intermediates and theoretical calculations to clarify structure-activity relationships. These approaches collectively enable the investigation and optimization of proton activation, electron transfer, and substrate hydrogenation pathways at the catalyst-electrolyte interface, ultimately aiming to upgrade NOCs into value-added products. Finally, the review discusses the challenges and future directions in designing high-efficiency ECH catalysts for organic nitrogen-containing feedstocks, with a focus on improving the application prospects of this technology in the artificial nitrogen cycle and its large-scale implementation.

A high-power, long-pulse-width acousto-optical Q-switched 1064 nm laser based on a multi-pass cavity (MPC) is reported in this paper. First, a plano-concave MPC structure satisfying the Q-preserving configuration was designed and introduced into an acousto-optical Q-switched plano-plano cavity Nd:YAG laser, extending the original laser cavity length by 1200 mm. The laser achieved a maximum average output power of 123.6 W with a repetition rate of 10 kHz. At this power level, the laser pulse width was broadened to 157.5 ns, which can be compared to 82.5 ns without the MPC structure, achieving a broadening ratio of 90.9%. The beam quality factors were Mx2 = 10.75 in the horizontal direction and My2 = 11.37 in the vertical direction. The experimental results demonstrate that inserting an MPC into the cavity is an effective method for broadening the pulse width of nanosecond lasers.

This study explored how fear conditioning and perceptual spatial separation affect the neural responses to target stimuli in the deep layers of the superior colliculus (deepSC) of awake rats. After electrodes were surgically implanted in the bilateral deepSC of all rats and a habituation period was completed, pre-fear conditioning tests, fear conditioning and conditioning control procedures, and post-fear conditioning tests were conducted in the awake state. The results showed that under the condition of perceptual spatial separation, fear conditioning significantly increased the stimulus-response coherence (S-R coherence) of the fine structure in the contralateral deepSC. However, no significant changes were observed in the amplitudes of the fine structure and envelope components before and after fear conditioning. S-R coherence is an important indicator of the precision of temporal expression, and fear conditioning and perceptual spatial separation are two common methods for introducing auditory attention. Therefore, based on the results of this study, we speculate that auditory attention improves the precision of the brainstem's response to target signals rather than enhancing the response strength. This study provides new insights into the neural mechanisms of auditory attention and the role of the deep layers of the superior colliculus in attention regulation.

This paper reports a continuous wave (CW) seeded cascaded femtosecond optical parametric amplification (OPA) system capable of delivering high average power in the telecom band. Pumped by a high-power Yb-fiber femtosecond amplifier operating at 50 MHz repetition rate, the two-stage OPA generates 1547 nm center-wavelength pulses with 120 fs pulse width and 1.8 W average power, achieving a 36% conversion efficiency. Benefiting from the low-noise characteristics of the narrow-linewidth CW seed laser, the output signal pulses exhibit a relative intensity noise integral of 0.35% over [3.3 Hz, 2.5 MHz] and a power fluctuation RMS of 1.06% over 2 h. This high-repetition-rate, high-power, low-noise telecom-band source holds significant potential for applications in laser processing, semiconductor etching, and bioimaging.

In this study, we present a high peak power Ho :YLF amplifier seeded by an electro-optically diodepumped Ho :GdVO4 laser operating at 2.05 μm. The diode-pumped Ho :GdVO4 laser, operating under a continuous-wave (CW) regime, achieved an output power of 7.1 W at an absorbed pump power of 28 W, resulting in a slope efficiency of 41.4

The chiral epoxidation of styrene and its derivatives is an important transformation that has attracted considerable scientific interest in the chemical industry. Herein, we integrate enzymatic catalysis and electrocatalysis to propose a new route for the chiral epoxidation of styrene and its derivatives. Chloroperoxidase (CPO) functionalized with 1-ethyl-3-methylimidazolium bromide (ILEMB) was loaded onto cobalt nitrogen-doped carbon nanotubes (CoN@CNT) to form a biohybrid (CPO-ILEMB/CoN@CNT). H2O2 species were generated in situ through a two-electron oxygen reduction reaction (2e–ORR) at CoN@CNT to initiate the following enzymatic epoxidation of styrene by CPO. CoN@CNT had high electroactivity for the ORR to produce H2O2 at a more positive potential, prohibiting the conversion of FeIII to FeII in the heme of CPO to maintain enzymatic activity. Meanwhile, CoN@CNT could serve as an ideal carrier for the immobilization of CPO-ILEMB. Hence, the coimmobilization of CPO-ILEMB and CoN@CNT could facilitate the diffusion of intermediate H2O2, which achieved 17 times higher efficiency than the equivalent amounts of free CPO-ILEMB in bulk solution for styrene epoxidation. Notably, an enhancement (∼45%) of chiral selectivity for the epoxidation of styrene was achieved.

The selective electro-oxidation reaction represents an efficient and environmentally friendly pathway to produce value-added chemicals from glycerol. Herein, we introduce a high-temperature cyanogel-reduction method to synthesize ultrathin RhCu bimetallenes (RhCu-BMLs) with varying Rh/Cu molar ratios and investigate their catalytic activity and selectivity for the glycerol electro-oxidation reaction (GEOR). Among these catalysts, the as-prepared Rh3Cu1-BMLs exhibit outstanding mass activity (579.3 A gRh � 1) for the GEOR under alkaline conditions, marking a 2.32-fold enhancement in mass activity (249.6 A gRh � 1) relative to single-component Rh metallens (Rh-MLs). Meanwhile, both experimental characterizations and theoretical calculations reveal that Cu atoms can attenuate OH- adsorption and block the oxygen insertion reaction for the generation of tartaric acid due to the electronic effect. Consequently, Rh3Cu1-BMLs achieve a remarkable 78.7 % selectivity for generating glyceric acid during GEOR. This work provides an important reference for fabricating bimetallic Rh -based catalysts and advancing the selectivity and activity in GEOR.

In this paper, we investigate the continuous-wave lasing characteristics of Ho :GdVO4 crystal under diode-pumping conditions. Using a 1.0 at.

Construction of an electroenzymatic cascade catalytic system based on a CPO-IL EMB @NMCNs-PEI biohybrid for selective oxidation of thioanisole to methyl phenyl sulfoxide with high catalytic activity.

The selective electrochemical conversion of glycerol into value-added products is a green and sustainable strategy for the biomass utilization. In this work, Au nanowires (Au-NW) modified with polyethyleneimine (PEI) molecule (Au-NW@PEI) is obtained by an up-bottom post-modification approach. Physical characterization, molecular dynamics simulation and density functional theory demonstrate that the loose-packed PEI monolayer firmly and uniformly distribute on the Au-NW surface due to the strong Au-N interaction. Electrochemical experiments and product analysis display that PEI modification significantly enhance the electro-activity of Au-NW for the glycerol electro-oxidation reaction (GEOR) due to the electronic effect. Meanwhile, the steric hindrance and electrostatic effect of PEI layer make the optimizing adsorption of intermediates possible. Therefore, the selectivity of C3 product glyceric acid over Au-NW@PEI is increased by nearly 20%. The work thus indicates that the rational design of metal-organic interface can effectively elevate the electro-activity and selectivity of Au nanostructures, which may have wide application in biomass development.

We proposed a Ho:GdVO4 laser operating at 2.05 μm which was directly in-band dual-end-pumped by a pair of 1.94 μm fiber-coupled laser diodes (LD). A Ho:GdVO4 crystal with doping of 1.0 at.% was used as the gain medium. In continuous-wave (CW) mode, we obtained the maximum output power of 6.5 W at 2047.9 nm with the absorbed pump power of 28 W, corresponding to a slope efficiency of 37.6 %. By using an LGS crystal as the electro-optical Q-switch, the highest peak power of 773.8 kW was obtained at a pulse repetition frequency (PRF) of 1 kHz, corresponding to a maximum pulse energy of 3.25 mJ and a pulse width of 4.2ns.

We proposed a Ho:GdVO4 laser operating at 2.05 mu m in-band directly pumped by the 1.94 mu m fiber-coupled laser diode, which electro-optically Q-switched by an LGS(La3Ga5SiO14) crystal. Adopting 1.0 at.%-doped Ho:GdVO4 crystal as the gain medium, a maximum output power of 6.5 W at 2047.9 nm with the absorbed pump power of 28 W was obtained in the continuous-wave mode, corresponding to a slope efficiency of 37.6 %. At a pulse repetition frequency of 1 kHz, the highest pulse energy of 3.25 mJ with a pulse width of 4.2 ns was achieved, corresponding to a peak power of 773.8 kW. In addition, the beam quality factor M2 was measured to be 1.9 at the maximum output level by the 90/10 knife-edge method. TEM00 propagation has been verified by a camera. To the best of our knowledge, this is the first demonstration of high peak power electro-optically Q-switched Ho: GdVO4 laser directly pumped by the 1.94 mu m laser diode.

A high-efficiency continuous-wave Tm:LSO laser in-band pumped by a FBG-locked Er-fiber laser at 1610 nm is demonstrated. A maximum output power of 3.2 W at 2055.1 nm was achieved with a slope efficiency of 51.7% with respect to the absorbed pump power. The beam quality factors M2 were measured to be 1.1 and 1.2 in horizontal and vertical directions, respectively, at the maximum output power.

Designing cost-efficient and active electrocatalysts are very crucial for their practical implementation in elec-trochemical energy conversion systems. Herein, a handy template-post phosphatization approach is adopted to achieve ultra-thin CoNi0.2P nanosheets attached to nickel foam (termed as CoNi0.2P-uNS/NF) nanohybrids. Profiting from ultra-thin construction and the optimization of electronic structure, CoNi0.2P-uNS/NF exhibits high electroactivity for hydrogen evolution reaction (HER), which only needs an overpotential of 43 mV to obtain the current density of 10 mA cm-2. Additionally, CoNi0.2P-uNS/NF also reveals prominent electroactivity for ethylene glycol oxidation reaction (EGOR) in an alkaline environment due to the surface electrochemical reconstruction. Additionally, CoNi0.2P-uNS/NF also reveals similar high electroactivity for glycerol and furfural derivatives oxidation reaction, revealing its potential as a composition-controlled platform catalyst. For practical application, CoNi0.2P-uNS/NF||CoNi0.2P-uNS/NF electrolyzer is assembled to directly electrolyze the hydrolysate of polyethylene terephthalate (i.e., the mixture of terephthalate and ethylene glycol) for the co-generation of formate and hydrogen, accompanying with lower integral electrolytic voltage (1.24 V) than traditional water splitting (1.53 V) at current density 50 mA cm-2. This work expands the territory for energy-saving co-generation of hydrogen and value-added chemical products.

Trichloroacetic acid (TCA), as a by-product of chlorination disinfection, is a highly carcinogenic chemical. Due to the widespread use of chlorination disinfection, it is critical to detect TCA in drinking water to decrease the incidence of disease. In this work, we developed an efficient TCA biosensor via electroenzymatic synergistic catalysis. The porous carbon nanobowls (PCNB) are prepared and wrapped by an amyloid like proteins formed by phase-transitioned lysozyme (PTL-PCNB), then, chloroperoxidase (CPO) is abounding to PTL-PCNB owing to its strong adhesion. The ionic liquid of 1-ethyl-3-methylimidazolium bromide (ILEMB) is co-immobilized on PTLPCNB to from CPO-ILEMB@PTL-PCNB nanocomposite to assist the direct electron transfer (DET) of CPO. The PCNB plays two roles here. In addition, to increasing the conductivity, it serves as an ideal support for holding CPO; The CPO-ILEMB@PTL-PCNB nanocomposite modified electrode presents high efficiency for sensing TCA. Through electroenzymatic synergistic catalysis, a wide detection range of 33 & mu;mol L-1 to 98 mmol L-1 can be achieved with a low detection limit of 5.9 & mu;mol L-1, and high stability, selectivity as well as reproducibility, which ensures its potential practical applicability. This work provides a new platform for the electro-enzyme synergistic catalysis in one pot.