Controllable Deposition of Bi onto Pd for Selective Hydrogenation of Acetylene

The rational regulation of catalyst active sites at atomic scale is a key approach to unveil the relationship between structure and catalytic performance. Herein, we reported a strategy for the controllable deposition of Bi on Pd nanocubes (Pd NCs) in the priority order from corners to edges and then to facets (Pd NCs@Bi). The spherical aberration-corrected scanning transmission electron microscopy (ac-STEM) results indicated that Bi2O3 with an amorphous structure covers the specific sites of Pd NCs. When only the corners and edges of the Pd NCs were covered, the supported Pd NCs@Bi catalyst exhibited an optimal trade-off between high conversion and selectivity in the hydrogenation of acetylene to ethylene under ethylene-rich conditions (99.7% C2H2 conversion and 94.3% C2H4 selectivity at 170 °C) with remarkable long-term stability. According to the H2-TPR and C2H4-TPD measurements, the moderate hydrogen dissociation and the weak ethylene adsorption are responsible for this excellent catalytic performance. Following these results, the selectively Bi-deposited Pd nanoparticle catalysts showed incredible acetylene hydrogenation performance, which provides a feasible perspective to design and develop highly selective hydrogenation catalysts for industrial applications

Systematic Study on the Precursor Reduction Kinetics and Growth Pattern for Size-Tunable Palladium Nanocubes

Unveiling the underlying chemistry during the growth of well-defined nanocrystals is a fundamental but challenging task in materials chemistry. Herein, Pd NCs with tunable sizes ranging from 4.5 to 23.5 nm have been synthesized in the presence of potassium acetate (KOAc). The Pd precursor variation trends of these preparation systems along with reaction time have been determined using a UV–vis spectrometer, and corresponding reduction kinetic parameters, including the apparent reduction rate constant (k) and activation energy (Ea), are calculated by regarding the reduction processes as quasi-first-order reactions. It is confirmed that the introduction of KOAc does not affect the value of the Ea of different reaction systems. The interrelationship of k, product size (d), and reaction temperature (T) is discussed in depth. Results indicate that the three parameters are closely related, and for given reaction systems, they are specified. With the careful investigation of six specific systems (reaction systems with 10 mM, 20 mM KOAc at 55 °C, with 5 mM, 10 mM KOAc at 65 °C, without KOAc at 75 °C, and with 5 mM KOAc at 85 °C), the growth pattern of Pd NCs is described with an empirical expression and is further confirmed as a synergistic result of k and T

Characteristics of deep water depositional system in Campos basin, Brazil

To make clear about the sedimentary facies types and distribution of deep water sandstone reservoirs in Campos basin of Brazil, this paper researches the characteristics of deep-water sedimentary system in Campos basin through the comprehensive analysis of drilling, logging and seismic data. There are 3 subfacies and 7 microfacies in the study area. There are 3 channels from south to north in Upper Cretaceous Maastrichtian, and the sedimentary incised valley and compound channels developed in micro-salt basin are the main deep water depositional types. The Paleocene to Eocene dominated by sedimentary incised valley and eroded compound channel deposits, also include 3 channel systems. From Oligocene to Miocene, the main deposition type is lobe, which is mainly distributed in central-north of the basin. Corresponding to deep water depositional stages, 3 kinds of depositional models are found. From Turonian to Maastrichtian of Upper Cretaceous, with tectonic uplift, strong source material supply, and the negative topography produced by salt rock movement providing favorable accommodation for sand deposition, the depositional model was terrigenous direct feed mechanism with sedimentary incised valley and compound channels in micro salt basin. From Paleocene to Eocene, as the amplitude of tectonic uplift reached the maximum and the accompanied erosion peaked, accommodation space offered by micro salt basin was leveled up; the depositional model was terrigenous direct feed mechanism with sedimentary valley and incised compound channels. From Oligocene to Miocene, because of sable tectonics, sea level fluctuation is the main controlling factor for deep water deposition, so the depositional model was wide shelf indirect feed mechanism with bypass incised valley and lobe. The analysis of the characteristics and controlling factors of the 3 types deep-water sedimentary systems during 3 different stages in Campos Basin can provide valuable reference for the oil exploration in deep-water deposits in the Campos Basin and across the world. Key words: Campos basin, deposition system, sedimentary facies, depositional model, reservoi

Difference analysis of gravity decollement structures and its effect on hydrocarbon accumulation: By comparing analysis of Lower Congo-Congo Fan Basin and Niger Delta Basin

Gravitational decollement is a structural pattern commonly developed in passive continental marginal basins on both sides of the Atlantic Ocean.Two different types of gravity decollement structures with transitional salt and marine mudstone as decollement layers are developed.Based on the stress mechanism, it can be divided into extensional zone, transitional zone and compressional zone successively from the continent to the ocean.In order to clarify the difference between those two types of gravitational decollement structures and their influence on oil and gas accumulation, this paper makes a comparative analysis of two representative basins, the Lower Congo-Congo Fan Basin and the Niger Delta Basin.Through comparing, the differences of structure patterns, sedimentary reservoir distribution characteristics and hydrocarbon accumulation were clarified in the same zone.On the whole, salt gravitational decollement in extensional zone shows that the salt structures are highly active, the oil-gas accumulation conditions are superior, and there are many oil-gas discoveries in this zone.In transitional zone, the intensity of salt activity is moderate and the degree of oil-gas enrichment is the highest.In compressional zone, the salt activity is strong with a large scale salt accumulation, poor source rock and reservoir, and rare oil-gas discoveries.The extensional zone of marine mudstone gravitational decollement is the main oil-gas accumulation area with relatively weak structure activity and good match between the reservoir and source rock.In transitional zone, it has strong extrusion stress, and large amount of mudstone has been accumulated there.The mud diapir is magnificent, and deep-slow diapir structure is the favorable oil-gas accumulation area.The compressional zone is dominated by typical thrust imbricate structure with good match of source rock, reservoir and oil source faults.The oil-gas enrichment in this zone is relatively high.Based on the analysis of those two types of gravitational decollement in source rock, reservoir and hydrocarbon accumulation, this paper have provided some references for the research related to gravitational decollement

Hepatoprotective effects of raspberry (Rubus coreanus Miq.) seed oil and its major constituents

Raspberry seed is a massive byproduct of raspberry juice and wine but usually discarded. The present study employed a microwave-assisted method for extraction of raspberry seed oil (RSO). The results revealed that omega-6 fatty acids (linoleic acid and γ-linolenic acid) were the major constituents in RSO. Cellular antioxidant enzyme activity such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were investigated in HepG2 cells treated with RSO. Induction of the synthesis of several antioxidants in H2O2-exposed HepG2 cells was found. RSO increased the enzyme activity of SOD, CAT, and GPx in H2O2-exposed HepG2. Furthermore, RSO inhibited the phosphorylation of upstream mitogen-activated protein kinases (MAPK) such as c-Jun N-terminal kinase (c-JNK) and extracellular signal-regulated kinase (ERK). Taken together, the possible mechanisms to increase antioxidant enzyme activities in HepG2 may through the suppression of ERK and JNK phosphorylation. Raspberry seed oil exhibited good effects on the activities of the intracellular antioxidant enzymes and seems to protect the liver from oxidative stress through the inhibition of MAPKs. © 201