Adsorption Of Pt Research Articles

Improving NiFe Electrocatalysts through Fluorination-Driven Rearrangements for Neutral Water Electrolysis.

Neutral electrolysis to produce hydrogen is prime challenging owing to the sluggish kinetics of water dissociation for the electrochemical reduction of water to molecular hydrogen. An ion-enriched electrode/electrolyte interface for electrocatalytic reactions can efficiently obtain a stable electrolysis system. Herein, we found that interfacial accumulated fluoride ions and the anchored Pt single atoms/nanoparticles in catalysts can improve hydrogen evolution reaction (HER) activity of NiFe-based hydroxide catalysts, prolonging the operating stability at high current density in neutral conditions. NiFe hydroxide electrode obtains an outstanding performance of 1000mA cm-2 at low overpotential of 218mV with 1000 h operation at 100mA cm-2. Electrochemical experiments and theoretical calculations have demonstrated that the interfacial fluoride contributes to promote the adsorption of Pt to proton for sustaining a large current density at low potential, while the Pt single atoms/nanoparticles provide H adsorption sites. The synergy effect of F and Pt species promotes the formation of Pt─H and F─H bonds, which accelerate the adsorption and dissociation process of H2O and promote the HER reaction with a long-term durability in neutral conditions.

Pt3Sn0.5Mn0.5 Intermetallic Electrocatalyst with Superior Stability for CO-Resilient Methanol Oxidation.

The sluggish kinetics of methanol oxidation reaction (MOR) and poor long-term durability of catalysts are the main restrictions of the large-scale applications of direct methanol fuel cells (DMFCs). Herein, we demonstrated an inspirational ternary Pt3Sn0.5Mn0.5/DMC intermetallic catalyst that reached 4.78 mA cm-2 and 2.39 A mg-1Pt for methanol oxidation, which were 2.50/2.44 and 5.62/5.31 times that of commercial PtRu/C and Pt/C. After the durability test, Pt3Sn0.5Mn0.5/DMC presented a very low current density attenuation (38.5%), which was significantly lower than those for commercial PtRu/C catalyst (84.2%) and Pt/C (93.1%). Density functional theory (DFT) calculations revealed that the coregulation of Sn and Mn altered the surface electronic structure and endowed Pt3Sn0.5Mn0.5 with selective adsorption of Pt for CO and Sn for OH, which optimized the adsorption strength for intermediates and improved the reaction kinetics of MOR. Beyond offering an advanced electrocatalyst, this study provided a new point of view for the rational design of superior methanol oxidation catalysts for DMFC.

Isomorphic substitution behavior of Pt on synthetic vernadite (δ-MnO2):A model reaction to elucidate the mechanism of Pt enrichment in marine ferromanganese crust

Marine ferromanganese crusts are considered to be the potential Pt deposits, and recent studies report a strong association between Pt and vernadite in these crusts. However, there are still uncertainties regarding the molecular processes involved in the enrichment of Pt by vernadite. This study investigates the adsorption behavior and molecular-scale immobilization mechanisms of Pt at water/vernadite interfaces through a combination of batch adsorption and desorption experiments, X-ray absorption fine structure (XAFS) analyses, and atomic resolution chemical imaging. Our findings suggest that the Pt enrichment on vernadite is attributed to an isomorphic substitution of Mn by Pt. The extended X-ray absorption fine structure (EXAFS) analysis reveals that Pt undergoes ligand exchange reactions during the enrichment process, and provides a comprehensive explanation of how Pt penetrates into the vernadite structure starting from the surface. Scanning transmission electron microscopy high-angle annular dark field (STEM-HAADF) observations visually confirm the infiltration of Pt atoms into the crystal structure of vernadite. Additionally, we demonstrate that the Pt enrichment in vernadite is a multi-stage chemical process. X-ray absorption near edge structure (XANES) analysis shows that Pt is initially rapidly adsorbed onto the surface of vernadite and then slowly oxidized. Our study provides a detailed understanding of the molecular-scale mechanisms involved in the adsorption of Pt onto vernadite and its subsequent structural incorporation. This knowledge is valuable for gaining insights into the Pt enrichment in marine ferromanganese crusts.

Functionalized palm biomass-derived activated carbon for the removal of Pt(IV) from a simulated leachate

Over the years, demand for Platinum Group Metals (PGMs) has grown steadily due to increased production of various advanced technologies, such as automotive and electronic products. PGMs are predominantly used in automotive catalysts in the automotive industry. Along with the increase in automotive production, deactivated automotive catalysts pose environmental and health hazards. These wastes are excellent alternative sources of PGMs, which can be exploited to bridge the gap between the demand and supply of PGMs. Adsorption is one of the most popular metal removal/recovery methods due to its various advantages, such as ease of use and cost-effectiveness. In consideration of this method, developing an inexpensive and efficient adsorbent is a crucial point. Thus, activated carbon (AC), derived from a palm kernel shell that is abundantly available in Indonesia, was functionalized using ionic liquid (ACIL) and used for Pt(IV) removal from a simulated automotive catalyst waste leachate. The functionalized AC showed a high adsorption capacity (178.6 mg g−1), in which the adsorption of Pt(IV) followed a chemisorption route, fitting with the monolayer model. The functionalized adsorbent also showed excellent performance during continuous Pt(IV) adsorption from simulated leachate. Recovery of precious metals, such as Pt(IV) and Pd(II), from the simulated leachate containing other metals was possible by maintaining the high hydrochloric acid concentration. Furthermore, targeted separation of Pt(IV) was achieved through sequential desorption using NaClO4. In addition, ACIL showed remarkable reusability after being used for three cycles without showing a noticeable decrease in performance. Thus, this study highlights the capability of a functionalized adsorbent from palm oil industry biomass to recover precious metals from simulated leachate of automotive waste.

Effect of spacer length between N atoms of linear alkyl triamines on adsorption of anionic platinum(IV) ions

In this study, the effect of carbon chain length between N atoms in linear alkyl triamines on the adsorption of anionic platinum ions was studied. For this purpose, bis(3-aminopropyl)amine (BAPA-SG) and diethylenetriamine (DETA-SG) groups were covalently bonded to the silica gel surface. The modified silica gels were characterized through C, H, N elemental analyses and FTIR spectroscopy before being utilized for adsorption and preconcentration Pt(IV) ions from aqueous solutions. Various factors influencing the batch adsorption of Pt(IV) ions with BAPA-SG and DETA-SG, such as nitric acid, chloride, initial Pt(IV) concentration, and contact time, were investigated. The adsorption of Pt(IV) ions was most efficient in the solutions containing 0.1 M hydronium and 0.1 M chloride ions. The adsorbed amount of Pt(IV) increased with an increase in the initial concentration of Pt(IV). The adsorption of Pt(IV) ions with BAPA-SG and DETA-SG reached equilibrium in 2 and 4 h, respectively. The kinetics of Pt(IV) adsorption on both modified silica gels were found to be compatible with the Pseudo-second-order kinetic model. Langmuir isotherm accurately described the adsorption Pt(IV) ions with BAPA-SG and DETA-SG, with maximum monolayer adsorption capacities of 158.7 and 227.3 mg/g, respectively. In the column solid phase extraction studies, Pt(IV) ions could be quantitatively recovered from 500 mL sample solutions using both modified silica gels by eluting with acidic thiourea solutions. The recovery of Pt(IV) by DETA-SG from chloride-containing solutions was more effective than with BAPA-SG. As a result, it was concluded that diethylenetriamine-bonded silica gel could adsorb Pt(IV) ions more effectively than bis(3-aminopropyl)amine bonded silica gel.

Advancements in sustainable platinum and palladium recovery: unveiling superior adsorption efficiency and selectivity with a novel silica-anchored acylthiourea adsorbent.

This study addresses the pressing issue of depleting natural resources of platinum group metals (PGMs), driven by their widespread use in modern applications and increasing demand for renewable energy technologies. With conventional sources dwindling, the search for economically viable recovery methods from alternative sources has become crucial. Our focus was on innovating efficient recovery strategies, leading to the development of two novel silica-anchored adsorbents: DTMSP-BT-SG, a highly efficient acylthiourea adsorbent, and BTMSPA-SG, a silica-anchored amine adsorbent. We conducted comprehensive experiments under PGM mining wastewater conditions, varying parameters such as adsorbent mass, pH, concentration, contact time, competing ions, and volume. DTMSP-BT-SG demonstrated exceptional performance, achieving maximum adsorption efficiencies of >98% for Pt and >99% for Pd at pH 2, 0.5 g L-1 dosage, and 5 mg L-1 concentration. In contrast, under the same conditions, BTMSPA-SG recovered <56% and <89% of Pt and Pd, respectively. The experimental data for both adsorbents were analysed using Langmuir and Freundlich isotherm models for concentration and pseudo-first and second-order models for contact time. The Langmuir model best described the adsorption data, indicating homogenous monolayer adsorption of Pt and Pd. The kinetic models suggested a pseudo-second-order process, implying chemisorption. Furthermore, in the presence of competing ions and other PGMs, DTMSP-BT-SG exhibited significantly higher recovery rates for Pt and Pd compared to BTMSPA-SG. Overall, DTMSP-BT-SG emerged as a more selective and efficient adsorbent across varied parameters. Its exceptional adsorption efficiency, coupled with cost-effectiveness, positions it as a promising and competitive recovery agent for extracting PGMs from mining wastewaters.

Enrichment and activation of cyano in cobalt hexacyanoferrate for specific recovery of ultra-low concentrations of platinum

Adsorption recovery of ultra-low concentrations (1 ppm) of platinum (Pt) was challenging due to the inferior sensitivity response and poor specific affinity between sorbents and target ions. Herein, enrichment and activation of the cyano group (CN) on cobalt hexacyanoferrate (CoHCF) were achieved by crystal facets engineering to capture Pt(Ⅱ) efficiently and specifically. The Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and density-functional theory (DFT) calculations results revealed that the activity and density of CN on the (220) facets were higher than that on the (200) facet. The Pt(Ⅱ) adsorption efficiency on the CN-enriched and -activated CoHCF (CoHCF(220)) reached 92.5%, which was 1.56 times higher than that on the original CoHCF (59.2%). The specific adsorption of Pt(Ⅱ) was driven by the coordination interaction between Fe-CN– and Pt, leading to the Pt(Ⅱ)-Pd(Ⅱ) separation efficiency attained 98.95% within 20 min. In addition, CoHCF(220) equipped with Pt(Ⅱ) could be further chemically reduced as a photocatalyst for hydrogen evolution. This study suggested an attractive strategy for the practical recovery of Pt(Ⅱ) and comprehensive utilization of ultra-low concentration Pt-containing wastewater.

Pt(IV)-ion imprinted ordered mesoporous organosilica for platinum preconcentration prior to electrothermal atomic absorption spectrometry determination in geological samples

Pt(IV) ion-imprinted thiocyanato-functionalized SBA-15 material (Pt(IV)S1) was proposed for preconcentration of Pt(IV) ions from digested geological samples before its electrothermal atomic absorption spectrometry (ETAAS) determination. The ion-imprinted material exhibited very good adsorption affinity towards Pt(IV) ions. Under the optimal pH (pH = 3) the maximum static adsorption capacity for Pt(IV) was equal to 175 mg g−1. The use of Pt(IV)S1 as an adsorbent allowed for the quantitative adsorption of Pt(IV) ions from solutions with concentrations up to 25 mg L−1. The creation of ion imprinted adsorption centres resulted in an increase of the adsorption rate and selectivity towards Pt(IV) compared to the similar non-ion imprinted material. The analytical procedure was based on the adsorption of Pt(IV) ions and dissolution of the Pt-loaded sorbent in a small volume of hydrofluoric acid before its dilution with 5% hydrochloric acid and introduction into an electrothermal atomizer. The enrichment factor of the proposed procedure was 38, while the limit of quantification was 0.079 mg kg−1.

Insight into the LED-induced deposition of Pt nanoparticles on a graphite matrix: Unravelling the photodeposition processes on materials different than semiconductors

A novel LED-assisted photodeposition process was used for the photoreduction of platinum nanoparticles on the exfoliated graphite surfaces. The photodeposition process on graphite was presented for the first time. It was found that the exfoliated graphite/Pt is graphite flakes with platinum nanocrystalline being homogeneously deposited on the surface of the carbon matrix. The mechanism of Pt photodeposition was based on the initial adsorption of Pt(IV) ions on the surface of the expanded graphite, and the reduction of Pt under the influence of UV radiation. Electrochemical measurements demonstrated that the EG/Pt composite exhibited good catalytic activity in the reaction of methanol electro-oxidation. The tested electrode maintained a high activity despite poisoning the Pt catalyst with intermediate products of methanol oxidation. This confirms that the LED-assisted photodeposition process can be an element of a novel approach for the synthesis of graphite-based materials for direct methanol fuel cells.

Catalytic Pt/Al2O3 Monolithic Foam for Ethanol Reforming Fabricated by the Competitive Impregnation Method.

Here, the synthesis of Pt/Al2O3 catalysts on a monolithic foam employing the competitive impregnation method is presented. NO3 - was used as a competitive adsorbate at different concentrations in order to delay the adsorption of Pt, minimizing the formation of Pt concentration gradients throughout the monolith. The catalysts' characterization includes the BET, H2-pulse titration, SEM, XRD and XPS techniques. The catalytic activity evaluation was performed under partial oxidation and autothermal reforming of ethanol in a short contact time reactor. The competitive impregnation method was able to produce better dispersion of the Pt particles through the Al2O3 foams. XPS analysis indicated the catalytic activity of the samples, by the presence of metallic Pt and Pt oxides (PtO and PtO2) in the internal regions of the monoliths. Compared to other Pt catalysts reported in the literature, the catalyst produced by the competitive impregnation method was revealed to be selective toward H2. Overall, the results showed that the competitive impregnation method employing NO3 - as the co-adsorbate is a promising technique to synthesize well dispersed Pt catalysts over α-Al2O3 foams.

Strong electrostatic adsorption of Pt over CoOx/TiO2 dual-support: Effect of synthesis pH on the catalytic activity for the CO oxidation in presence of hydrogen

Highly dispersed Pt-based catalysts were prepared by Strong Electrostatic Adsorption (SEA) for the PROX reaction. The effect of the catalyst synthesis pH was investigated to control the metal-support interactions for the system: Pt supported onto cobalt oxide, previously supported on TiO2. The Pt/CoOx/TiO2 catalysts were prepared in a pH range of 3.0–9.0, obtaining Pt dispersion values above 90% with Pt crystallite sizes of 1–2 nm. The effect of the synthesis pH was correlated with the concentration of (Pt-CoOx)i interfacial sites, and this, in turn, with the catalytic activity. The concentration of (Pt-CoOx)i interfacial sites was higher for the most active catalyst, which was prepared at a condition that ensures a higher selective-SEA of Pt over the co-support (pH = 6.0). This study shows that the synthesis pH can determine the concentration and type of active sites and paves the way to use SEA to control the activity of dual-supported catalysts.

Synthesis and Application of Positively Charged and Magnetically Separable Magnetite/Silica-Ammonium as an Effective Platinum(IV) Adsorbent

Platinum is a valuable metal that is widely used in industry, electronics, and catalysts. The use of Platinum has a significant impact on the production of waste, necessitating effective metal recovery. This study investigated Platinum (IV) recovery from wastewater using a positively charged and magnetically separable Magnetite/Silica-Ammonium (MSA). The MSA was prepared by co-precipitation procedure of silica-decorated quaternary ammonium in the Fe3+/Fe2+solution. The characterization result of the MSA by FT-IR, X-ray diffraction (XRD), SEM-EDX, and Vibration Sample Magnetometer (VSM) demonstrated the success of MSA synthesis. The application of MSA to the Pt (IV) solution occurred at pH optimum 6,0 with the easy and quick retraction of MSA-loaded Pt (IV) by 29.3 emu/g magnetic strength of an external magnet. The adsorption isotherm study followed the Freundlich model (R2=0.9895) with theKF=2.57×10-2mol/g. The monolayer capacity by Langmuir showed the remarkable performance of 139.09 mg/g adsorption capacity through the ion exchange interaction mechanism based on the Dubinin-Radushkevich energy (ED-R=8,3 kJ/mol). The kinetics study was fitted well to the Pseudo-second-order model indicated the fast adsorption of Pt (IV) into the MSA surface.

Enhancing Ethanol Electrooxidation Stability over PtIr/GN Catalysts by In Situ Formation of IrO2 at Adjacent Sites

PtIr alloy is considered as one of the most promising catalysts for ethanol electrooxidation due to its excellent C–C bond breaking and dehydrogenation abilities. However, a small amount of intermediate species produced by ethanol oxidation can still poison Pt, thereby affecting the stability of ethanol oxidation. Here, graphene supported PtIr nanoparticles (PtIr/GN) with a Pt: Ir atomic ratio of 3:1 is synthesized by a simple hydrothermal reduction and thermal annealing. The physicochemical analyses show that IrO2 is formed in situ in PtIr/GNs (O) during annealing and located adjacent to PtIr alloys. IrO2 and PtIr are evenly dispersed on GNs. The electrochemical results indicate that PtIr/GNs (O) has higher catalytic activity and stability for ethanol electrooxidation than PtIr/GNs. After 1000 voltammetric cycles, the peak current density for PtIr/GNs (O) is 2.5 times higher than that for PtIr/GNs. The outstanding electrochemical performance of PtIr/GNs (O) is derived from PtIr alloy that promotes the cleavage of the C–C bond and weakens the adsorption of Pt to intermediate species, IrO2 that improves the tolerance of Pt to CO-like species and enhances the structural stability of Pt, and PtIr alloy and IrO2 in adjacent positions that synergistically improve the stability of catalytic ethanol oxidation.

Catalyst with a low load of platinum and high activity for oxygen reduction derived from strong adsorption of Pt−N4 moieties on a carbon surface

Minimizing the use of platinum (Pt) in catalysts for the oxygen reduction reaction (ORR) is critical for the commercial application of fuel cells. Here, we report a highly active carbon-supported catalyst with a low loading of Pt nanoparticles (Pt/C-N, 7.13 wt% Pt), prepared using a small molecular Pt complex containing Pt−N4 moieties as the Pt precursor. It was confirmed that Pt nanoparticles with an average diameter of <3 nm were uniformly adsorbed on a nitrogen (N)-doped carbon surface by carbothermal reduction of a composite composed of Pt(NH3)42+ ions and carbon via strong electrostatic attraction. More importantly, it is found that single atoms of platinum and pyridinic N active sites for the ORR are created during this process. The Pt/C-N catalyst shows very high ORR performance in acidic media, with a mass activity of 108 mA/mgPt−1 (at 0.9 V vs. RHE), which is three times greater than that of a commercial Pt/C catalyst (20 wt% Pt, 35 mA/mgPt−1). The high ORR activity of the Pt/C-N catalyst is ascribed to the synergistic catalytic effect of the Pt nanocrystals and the atomically dispersed active sites, which include single atoms of Pt and pyridinic N.

Pt/Au surface adsorption on the ZnO surface: A first-principles study

The adsorption of Pt/Au on the surface of ZnO is investigated in this paper, which discusses possible adsorption sites, electronic properties as well as optical adsorption spectrum. Results show that the stable adsorption site of Pt atom is T. O site and Au atom is more suitable for B site. Pt/Au noble metal is adsorbed on the surface of ZnO by the van der Waals bonds, and do not form a conventional Schottky contact. The adsorption of Pt will narrow the band gap to 0.06 eV to form a semiconductor, and Au adsorption makes it metal. Obviously infrared absorption peak appears in the absorption spectrum along with Pt/Au adsorbed on the surface.

Speciation and separation of platinum(iv) polynuclear complexes in concentrated nitric acid solutions.

Understanding the solution chemistry of Pt(iv) is crucial for the hydrometallurgy of precious metals. To gain such an understanding, the speciation and separation of Pt(iv) complexes in concentrated HNO3 solutions were investigated via Pt LIII edge X-ray absorption fine structure (XAFS) spectroscopy. The XAFS results for concentrated HNO3 solutions of Na2Pt(OH)6 revealed the dominant presence of Pt polynuclear complexes, wherein the formation of Pt(iv) polynuclear complexes depended on the metal concentration and the Na2Pt(OH)6 dissolution temperature. The dominant species present in a heated nitrate solution of 0.90 g-Pt L-1 and a non-heated nitrate solution of 3.2 g-Pt L-1 were dinuclear Pt(iv) complexes, whereas those in a heated solution of 3.0 g-Pt L-1 were predominantly larger polynuclear complexes, such as, tetra- and hexa-nuclear complexes. The presence of larger Pt(iv) complexes was confirmed via XAFS spectroscopy, wherein the adsorption of Pt(iv) ions from a 10 M HNO3 solution by a chelating resin functionalised with iminodiacetic acid and a strongly basic anion-exchange resin bearing trimethyl ammonium nitrate was examined. The adsorption of 50 mg L-1 of Pt(iv) by the two resins was tested using aqueous solutions diluted from heated HNO3 solutions with varying metal concentrations, and also from a non-heated solution. We found that Pt(iv) complexes from heating solutions containing high Pt(iv) concentrations displayed high adsorption percentages. In addition, the selective adsorption of Pt(iv) over Pd(ii), Ag(i), Cu(ii), Ni(ii), and Fe(iii) from a 10 M HNO3 solution was achieved using a strongly basic anion-exchange resin.

Recovery of platinum (IV) from aqueous solutions using 3-aminopropyl(diethoxy)methylsilane functionalized bentonite

Platinum, naturally found in a few parts of the world, is one of the most widely used precious elements and its recycling from waste components is very important due to demand. However, not as much attention has been given toward its recovery from aqueous solutions. This present study is aimed at recovering platinum (Pt(IV)) from aqueous solutions such as mining wastewaters using bentonite functionalized with 3-aminopropyl(diethoxy)methylsilane (APDEMS). The study exploited the novelty of using a cost-effective natural mineral, bentonite, as a support base to which amine groups, that have a high affinity for Pt(IV), could be anchored. The approach involved characterizing the natural and functionalized bentonite. Adsorption experiments were conducted in batch mode under varying conditions, namely: adsorbent dosage, pH, initial concentration, and competing ions. The data were fitted using various kinetic and isothermic models to understand the adsorption mechanism. The results showed that >85% of Pt(IV) in solution was recovered at a dosage of 10 g L−1 of the adsorbent at pH 2, within 90 min of contact. The adsorption of Pt(IV) increased by >5% in the presence of other ions, most likely due to synergistic effects. The adsorption of Pd(II), Ir(III), Rh(III), Os(III), and Ru(III) was also enhanced along with that for Pt(IV). Adsorption was found to proceed via the Langmuir isotherm and the pseudo second-order kinetic model, implying monolayer coverage and chemisorption, respectively. The successful synthesis of APDEMS-functionalized bentonite and its efficiency in adsorbing Pt(IV) from aqueous solutions make it a potential adsorbent for application in the mining industry.

Co-deposits of Pt and Bi on Au disk toward formic acid oxidation

Presented in this work is an investigation of co-deposits of Pt and Bi on Au disk (Pt-Bi/Au) toward formic acid oxidation (FAO) using voltammetry and X-ray photoelectron spectroscopy (XPS). The co-deposits of Pt and Bi on Au were prepared using an irreversible method in a mixed solution of Pt ion (1 mM) and Bi ion (5 mM), and the amount of co-deposits was controllable by the number of deposition cycles. The voltammetric studies revealed that the Pt-Bi/Au surfaces presented the characteristics of Pt, Bi, and Au depending on the number of deposition cycles. A detailed analysis of semi-quantitative results of XPS combined with hydrogen coverage on Pt and covered fraction of Au surface suggested two aspects of Pt-Bi co-deposits. One is that during co-adsorption, Bi adsorbing with a low efficiency enhanced irreversible adsorption of Pt. The other is that the Pt-Bi co-deposits would be an alloy of Pt-Bi when the Pt amount was low or Pt deposits enriched with Bi in surface regions when the Pt amount was high. The best FAO catalytic efficiency among the investigated Pt-Bi/Au surfaces was ~ 14 mA/cm2, which was higher than that of plain Pt deposits on Au (~ 6 mA/cm2) and comparable to that of sequentially prepared Bi-modified Pt deposits on Au (Bi/Pt/Au, ~ 20 mA/cm2). Because of a similarity in compositions and catalytic performances of the best Pt-Bi/Au and Bi/Pt/Au, the preparation procedure was concluded not to be critical so that the co-deposition method was more beneficial in terms of the number of deposition cycles in manufacturing electrocatalysts toward FAO.

Decoupling Strategy for Enhanced Syngas Generation from Photoelectrochemical CO2 Reduction.

SummaryPhotoelectrochemical CO2 reduction into syngas (a mixture of CO and H2) provides a promising route to mitigate greenhouse gas emissions and store intermittent solar energy into value-added chemicals. Design of photoelectrode with high energy conversion efficiency and controllable syngas composition is of central importance but remains challenging. Herein, we report a decoupling strategy using dual cocatalysts to tackle the challenge based on joint computational and experimental investigations. Density functional theory calculations indicate the optimization of syngas generation using a combination of fundamentally distinctive catalytic sites. Experimentally, by integrating spatially separated dual cocatalysts of a CO-generating catalyst and a H2-generating catalyst with GaN nanowires on planar Si photocathode, we report a record high applied bias photon-to-current efficiency of 1.88% and controllable syngas products with tunable CO/H2 ratios (0–10) under one-sun illumination. Moreover, unassisted solar CO2 reduction with a solar-to-syngas efficiency of 0.63% is demonstrated in a tandem photoelectrochemical cell.

The influence of alkanolamine in the formation of Pt nano- and microstructures

Start your abstract here Pt nano- and microstructures have been produced by a solvothermal technique in the presence of diethanolamine (DEA) as a reducing and capping agent. The effect of DEA concentration on Pt properties (structural and morphological) was discussed in detail. A lower DEA concentration produces nanoscale size particles while at higher concentration results in micro-flower structures. Pt crystallinity is enhanced with respect to the increment of DEA concentration in the order of 0.43 M >0.29 M >0.14 M. The presence of amino groups is confirmed by the intense band at ∼1087 cm−1 and absorption peak at 1446 cm−1 corresponds to C-N and N-H bending vibration mode of the amine group. The UV-Visible adsorption peak at 282 nm, due to adsorption of Pt (IV) disappeared implying that the Pt (IV) species has been reduced to Pt (0) valent confirming that DEA acted as a reducing agent. A possible reaction mechanism has been proposed.