查找使用阿拉丁产品的科研文献

Pd nanocrystal sensitization two-dimension porous TiO2 for instantaneous and high efficient H2 detection

Ding Wang,Jialin Yang,Liping Bao,Yu Cheng,Liang Tian,Qingxiang Ma,Jingcheng Xu,Hui-Jun Li,Xianying Wang

Hydrogen (H 2 ) molecules are easy to leak during production, storage, transportation and usage. Because of their flammability and explosive nature, quick and reliable dectection of H 2 molecule is of great significance. Herein, an excellent H 2 gas sensor has been realized based on Pd nanocrystal sensitized two-dimensional (2D) porous TiO 2 (Pd/TiO 2 ). The formation of 2D porous TiO 2 with the removal of graphene oxide template has been monitored by an in-situ transmission electron microscope. It is found that the size of the GO template can be almost completely replicated by 2D TiO 2 . The Pd/TiO 2 sensor exhibited an instantaneous response and a satisfactory low detection limit for H 2 detection. These excellent gas-sensing performances (good selectivity, unique linearity response and high stability) can be attributed to the unique 2D porous structure and the synergistic effect between oxidized Pd and TiO 2 , including the unique adsorption properties of O 2 or/and H 2 on Pd/TiO 2 , the reaction between PdO and H 2 gas, and the regulated depletion layer arising from p-type PdO to n -type TiO 2 . This work demonstrates a rational design and synthesis of highly efficient H 2 sensitive materials for energy and manufacturing security.

Achieving controlled vanillin HDO by modulation of oxygen vacancies on the Pd/Nb2O5 surface

Xuan Liu,Hao Xu,Hao Li

The conventional Hydrogenation deoxygenation (HDO) process is accompanied by harsh reaction conditions (high temperature, high hydrogen pressure, and long reaction time), leading to problems such as easy catalyst deactivation and poor product selectivity. Therefore, the design of hydrodeoxygenation catalysts that can achieve controllable reaction paths, directional product selectivity and high reaction efficiency under mild conditions has become the key to the problem. Phenolic resin (RF) formed by resorcinol–formaldehyde condensation reaction was introduced as a carbothermal reducing agent to prepare oxygen defect-rich Pd/Nb 2 O 5 -T-RF catalysts. The concentration of oxygen defects on the catalyst surface was changed by adjusting the calcination temperature, which affected the electronic properties and acid properties of the catalyst surface interface and promoted the C-O bond breaking. At 25 ℃ and 80 min, Pd/Nb 2 O 5 -700-RF obtained 100 % Vanillin (VAN) conversion and 98.0 % 2-methoxy-4-methylphenol (MMP) selectivity, and the catalytic performance was significantly better than that of the catalysts without RF treatment as well as other calcination temperatures. Characterization and experimental results showed that the electron-deficient oxygen defect facilitated the adsorption and activation of vanillin and vanillyl alcohol, while promoting the hydrogen spillover on the catalyst surface and improving the HDO catalytic performance. In addition, the method is universal for reducible transition metal oxides and can be further extended to different metal oxide catalysts and applied to other fields.

Confinement of ultrasmall Pd nanoparticles by layered covalent triazine frameworks for semihydrogenation of acetylene

Jiqiu Zhang,Guanyin Zhang,Liang He,Yuzhen Shi,Rongrong Miao,Yuanzhi Zhu,Qingqing Guan

Acetylene hydrogenation is an important reaction in the petrochemical industry, the key is to develop efficient and selective catalyst. In this work, a highly crystalline layered covalent triazine frameworks (CTFs) with excellent thermal stability was used as carbon support to immobilize ultrasmall Pd nanoparticle for semihydrogenation of acetylene. Downsizing the particle sizes were realized by dual-solution assisted precursor mixture and using H 2 instead of NaBH 4 as reducing agent. The pore confinement effect of CTFs and the electronic intercalation from N atoms play key roles in improving the catalytic activity and stabilizing the Pd nanoparticles. The Pd/CTFs-H 2 catalyst exhibits 100% acetylene conversion and 99.9% ethylene selectivity at 250 °C and space velocity of 110,000 h −1 . The life test (>150 h), cycle test and chemical stability test demonstrated the long-term stability of the Pd/CTFs-H 2 . The process mechanism of selective hydrogenation of acetylene in this catalyst is investigated by the in-situ infrared spectra .

Lysosome activable polymeric vorinostat encapsulating PD-L1KD for a combination of HDACi and immunotherapy

Fengkun Lu,Lei Hou,Sizhen Wang,Yingjie Yu,Yunchang Zhang,Linhong Sun,Chen Wang,Zhiqiang Ma,Feng Yang

Support-Induced unusual size dependence of Pd catalysts in chemoselective hydrogenation of para-chloronitrobenzene

Xiaohui Zhang,Qingqing Gu,Yanfu Ma,Qiaoqiao Guan,Rui Jin,Hengwei Wang,Bing Yang,Junling Lu

For supported metal catalysts, the underlying support not only disperses and stabilizes metal particles, but also modulates their electronic structures remarkably, and even directly participates in catalytic reactions. Here we report that Pd nanoparticles (NPs) supported on oxygen-functionalized carbon black (Pd/O-C) show an unexpected inverse trend of selectivity on Pd particle size in chemoselective hydrogenation of para -chloronitrobenzene ( p -CNB), compared to those on carbon black (Pd/C). In situ X-ray photoemission spectroscopy reveals that the Pd NPs are more positively charged with decrease of particle size in both samples, while the Pd NPs in Pd/O-C have relatively higher fractions of positive Pd δ+ species than those in Pd/C with similar sizes. Fourier transform infrared spectroscopy shows that the balance of positive Pd δ+ species strongly modulates the competitive adsorption of -NO 2 and -Cl group in p -CNB according to their different electronegativities. As a consequence, we, for the first time, demonstrate that a moderate positive charge of Pd NPs is essential to improve the p- chloroaniline ( p -CAN) selectivity, while too high or too low positive charge could impel the adsorption of the less negatively charged -Cl group, thus generating the dehalogenated aniline by-product. These findings suggest that precise tailoring of the electronic structures of metal NPs could be essential for design of high chemoselective metal catalysts.

Pd Nanoparticles Loaded on Ceramic Membranes by Atomic Layer Deposition with Enhanced Catalytic Properties

Jia Lu,Qingqing Chen,Sibai Chen,Hong Jiang,Yefei Liu,Rizhi Chen

Atomic layer deposition (ALD) was adopted for the first time to load Pd nanoparticles on Al2O3 ceramic membranes (CMs) for fabricating catalytic membranes (Pd/CMs). The membrane surface was functionalized with the deposition of TiO2 by ALD and subsequent calcination under different atmospheres [CM-TiO2-A, obtained by calcination under an atmosphere of pure argon; CM-TiO2-H, obtained by calcination under a mixed atmosphere of H2 and Ar (H2/Ar = 1:9 in volume)]. The influence of the TiO2 deposition on the microstructure of catalytic membranes and their catalytic performance in p-nitrophenol reduction to p-aminophenol were investigated in detail. The catalytic activity of Pd/CM-TiO2-H improved by 1.9 times compared to Pd/CM, and 100% conversion of p-nitrophenol to p-aminophenol can be achieved. The X-ray photoelectron spectroscopy (XPS), inductively coupled plasma emission spectroscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy results indicate that the ALD of TiO2 and subsequent calcination under a 10% H2 atmosphere can produce more surface oxygen vacancies, providing more active sites for Pd(hfac)2 adsorption and then promoting the loading of Pd nanoparticles. The XPS and H2 temperature-programmed reduction results suggest that calcining TiO2 under the 10% H2 atmosphere is more beneficial for the removal of the hfac ligands and the reduction of Pd(hfac)2, leading to a higher Pd0 ratio. These two aspects contribute to the superior catalytic activity of Pd/CM-TiO2-H.

Predicting cerebral acetylcholine dynamics with huperzine A pharmacokinetics in blood via mPBPK-PD modeling

Jiaying Wang,Yangfan Zhang,Haoqian Wu,Siqi Yu,Xiaoying Cai,Youying Zhang,Jian Chen,Zixing Chen,Xiao Zheng,Haiping Hao

Huperzine A (HupA) is a highly selective, reversible acetylcholinesterase (AChE) inhibitor that exhibits neuroprotective effects and is clinically used to manage benign memory decline. However, the specific relationship between the pharmacokinetic (PK) profile of HupA and cerebral acetylcholine (ACh) dynamics remains poorly characterized. Here, we characterize the PK-pharmacodynamic (PD) properties of HupA in rats under both physiological and pathological conditions. Following a single intramuscular injection, HupA exhibits a short half-life but rapid brain penetration, while multiple dosing significantly enhances its brain exposure. In a middle cerebral artery occlusion (MCAO) rat model, HupA demonstrates increased brain distribution. Furthermore, HupA elevates ACh concentrations across multiple brain regions, concurrently modulating several monoamine neurotransmitters. Using a minimal physiologically based pharmacokinetic-pharmacodynamic (mPBPK-PD) modeling approach, cerebral ACh dynamics were accurately predicted based on the pharmacokinetics of HupA in systemic circulation. The developed mPBPK-PD model exhibits robust predictive performance and holds potential for guiding the optimization of clinical dosing regimens and improving the therapeutic efficacy of HupA.

Facet-dependent degradation of Pd nanocubes and surface stabilization via atomic-level Pt modification

Chen Li,Zhe Gong,Peiqi Huang,Yongchao Wang,Mingxing Gong

Single-crystal Pd nanocubes with preferential (100) facets were synthesized as model catalysts to probe the intrinsic activity and stability limits of Pd-based electrocatalysts for methanol oxidation. The nanocubes deliver a mass activity of 1140 mA mg −1 at 0.9 V, nearly twice that of Pt/C. Despite this impressive activity, accelerated durability tests reveal pronounced performance decay, arising from facet-dependent structural degradation rather than catalyst detachment. Identical-location TEM combined with in-situ Raman spectroscopy uncovers that adsorbed hydroxyl intermediates trigger Pd dissolution, lattice reconstruction, and interparticle coalescence, leading to severe loss of electrochemically active surface area. Guided by these mechanistic insights, we introduced an atomic-level surface modification by depositing an ultrathin Pt overlayer on Pd nanocubes. The resulting Pd@Pt nanocubes preserve the cubic architecture, achieve an enhanced mass activity of 1506 mA mg −1 , and exhibit substantially improved stability with >50% retention after extended operation. The suppression of hydroxyl-induced poisoning and coalescence highlights the role of interfacial electronic tuning in stabilizing active surfaces. This work elucidates the facet-specific degradation pathways of Pd catalysts and establishes surface modification as a generalizable strategy toward designing durable, high-performance electrocatalysts for alcohol oxidation.

Oxygen-Vacancy-Engineered Pd-WO3–x for Enhanced Plasma-Catalyzed CO2 Hydrogenation to CO

Can Cheng,Yaolin Wang,Jia-nan Wang,Haomiao Xu,Wenjun Huang,Zhisong Liu,Wei Li,Yuyang Li,Zan Qu,Xin Tu,Naiqiang Yan

Plasma-catalytic CO2 hydrogenation to CO offers a promising route for carbon-neutral chemical synthesis. However, its advancement is constrained by low energy efficiency and limited mechanistic insight. Here, we developed an oxygen vacancy-engineered Pd-WO3–x catalyst supported on nickel foam (NF), which exhibits enhanced performance in ambient plasma-driven CO2 conversion. The system leverages the conductive properties of NF to spatially divide the discharge zone into streamer and filamentary discharge zones, thereby enhancing plasma activation and interfacial charge transfer. Catalyst characterization reveals that Pd plays a critical role in stabilizing metastable oxygen vacancies (OVs) within WO3–x, which function as electron reservoirs to promote CO2 dissociation into CO. Density functional theory calculations and in situ spectroscopic studies confirm that Pd facilitates H2 dissociation, while vibrationally excited CO2 generated in the plasma gas phase preferentially adsorbs at OV sites. At a specific energy input of 33.6 kJ L–1, the system demonstrates superior performance, achieving 54.9% CO2 conversion with 99.8% selectivity toward CO, surpassing typical plasma-catalytic benchmarks. The catalyst exhibited good stability over 100 h of continuous operation, with a slight decrease in CO2 conversion (<10%) and nearly unchanged CO selectivity (>99%) due to strong metal–support interactions and the conductive nature of NF. This work demonstrates that OV engineering provides a promising strategy for designing efficient plasma-catalytic systems for CO2 conversion.

Hydrogen accelerated regeneration of FeII in Fenton reaction enhanced by Pd/MOF-808(Zr)

Yang Hu,Hai-Liang Yang,San-Jian Ma,Juan-Hong Li,Xin Liu,Yong-Jing Tian,Long Jin,Zi-Xia Lin

The promotion of Fenton process in organic wastewater treatment has been hindered by the disposal of large amounts of iron sludge derived from the excess addition of ferrous salt. The operation of the Fenton reaction could be maintained using trace level Fe II through the effective acceleration reaction of active hydrogen. However, the H 2 which is the precursor of active hydrogen is insoluble in water. Herein, the composite catalyst Pd/MOF-808(Zr) was introduced into the H 2 -Fenton system to enhance the adsorption and activation of this reducing gas. In this novel improved Fenton system called MHACF-MOF-808(Zr), the hydroxyl radical would be unceasingly produced based on the unceasingly recycling of FeII/FeIII at normal temperature and pressure. 15 mg L −1 sulfamethazine could be thoroughly degraded during 2 h reaction process in the initial condition of 60 mL min −1 H 2 , 20 μmol L −1 Fe II , pH 3, 20 mmol L −1  H 2 O 2 and 2 g L −1  Pd/MOF-808(Zr). And so did 10 mg L −1 2,4-Dichlorophenol. The activity and stability of Pd/MOF-808(Zr) could be maintained after at least 6 consecutive reaction cycles. It provides new insight for improving the inherent shortcoming of the Fenton reaction which will generate large amounts of iron sludge.

Ultrafine Pd@PdPt nanowires with a single-atom alloy shell for efficient formate oxidation

Yu-Chuan Jiang,Yu Ding,Fu-Min Li,Shi-Bin Yin,Dong-Sheng Li,Xi-Fei Li,Yu Chen

The intrinsically sluggish kinetics of Pt towards the formate oxidation reaction (FOR) severely impedes its application in direct formate fuel cells (DFFCs). This study reports the synthesis of ultrafine Pd@PdPt nanowires (NWs) with a Pd–Pt single-atom alloy shell via an atomic galvanic displacement reaction. Pd@PdPt0.024 NWs with optimized composition exhibit a remarkable promoted specific activity of 98.2 A m−2 at 0.59 V towards the FOR, which is a 6.5- and 117.7-fold activity enhancement compared to original Pd NWs and commercial Pt catalysts. Density functional theory (DFT) calculations reveal that the electronic interaction between Pd and Pt as well as the modified Pt coordination environment endow the atomically dispersed Pt active site with an altered d-band structure and unique adsorption properties with a broken scaling relationship. The development of Pd@PdPt0.024 NWs will stimulate deeper insight into the FOR mechanism on Pt and hold promise for practical applications in DFFCs.

Constructing Polyphosphazene Microsphere-Supported Pd Nanocatalysts for Efficient Hydrogenation of Quinolines under Mild Conditions

Xiufang Chen,Qingguang Xiao,Yiguo Yang,Bo Dong,Zhengping Zhao

The efficient hydrogenation of N-heterocycles with H2under mild conditions remains a significant challenge. In this work, polyphosphazene (PZs) microspheres, novel organic–inorganic hybrid materials possessing unique –P=N– structural units and a diverse range of side groups, were used to serve as support for the design of a stable and efficient Pd nanocatalyst (Pd/PZs). The PZs microspheres were prepared by self-assembly induced by precipitation polymerization, and Pd nanoparticles were grown and loaded on the support by a chemical reduction process. Several characterization techniques, including XRD, FTIR, SEM, TEM, XPS, BET and TGA, were used to study the structural features of the nanocomposites. The results revealed that Pd nanoparticles were uniformly distributed on the PZs microspheres, with primary sizes ranging from 4 to 9 nm based on the abundance of functional P/N/O groups in PZs. Remarkably high catalytic activity and stability were observed for the hydrogenation of quinoline compounds using the Pd/PZs nanocatalyst under mild conditions. Rates of 98.9% quinoline conversion and 98.5% 1,2,3,4-tetrahydroquinoline selectivity could be achieved at a low H2pressure (1.5 bar) and temperature (40 °C). A possible reaction mechanism for quinoline hydrogenation over Pd/PZs was proposed. This work presents an innovative approach utilizing a Pd-based nanocatalyst for highly efficient multifunctional hydrogenation.