Atomic Design and Fine-Tuning of Subnanometric Pt Catalysts to Tame Hydrogen Generation

ACS Catalysis ◽  
2021 ◽  
pp. 4146-4156
Author(s):  
Jie Yang ◽  
Wenzhao Fu ◽  
Chaoqiu Chen ◽  
Wenyao Chen ◽  
Wugen Huang ◽  
...  
Keyword(s):  
Hydrogen Generation ◽  
Fine Tuning ◽  
Pt Catalysts

Methanol Reforming Over PT Catalysts for Polymer Electrolyte Membrane Fuel Cells

2006 ◽  
Author(s):  
Taehee Lee ◽  
Joongmyeon Bae ◽  
Ju-Yong Kim
Keyword(s):  
Hydrogen Generation ◽  
Polymer Electrolyte Membrane ◽  
High Energy ◽  
High Energy Density ◽  
Pt Catalysts ◽  
Methanol Reforming ◽  
Electrolyte Membrane ◽  
Cerium Oxides ◽  
Lower Temperature ◽  
Very High

An experimental investigation on hydrogen generation from methanol using Pt catalysts is presented in this paper. Methanol has the advantages of high energy density, high reforming activity and low CO selectivity at low temperatures. At present Cu-based catalysts are widely used for methanol reforming. But they are pyrophoric and thermally unstable, which causes issues in operating a real system. Pt catalysts dispersed on cerium oxides were tested for methanol reforming to resolve the problems. Steam reforming over Pt/cerium oxides showed the low conversion ratio less than 90% and the high CO concentration of about 15% at 400 °C. Autothermal reforming by adding O2 rapidly promoted the conversion of methanol and reduced the concentration of CO at lower temperature. Increasing the amount of dispersed Pt, the range of 0.5–3.0 wt%, shifted the reforming trends towards lower temperature and decreased the concentration of CO. To achieve more production rate within a given catalyst bed, catalysts coated monolithic honeycomb is prepared. It showed very high conversion at space velocities of up to 60,000/h.

scholarly journals Atomic design and fine-tuning of sub-nanometric Pt catalysts to tame hydrogen generation

2020 ◽  
Author(s):  
Jie Yang ◽  
Wenzhao Fu ◽  
Chaoqiu Chen ◽  
Wenyao Chen ◽  
Wugen Huang ◽  
...  
Keyword(s):  
Active Site ◽  
Catalytic Mechanism ◽  
Hydrogen Generation ◽  
Atomic Layer ◽  
Fine Tuning ◽  
Superior Performance ◽  
Single Atom ◽  
Intrinsic Activity ◽  
Atomic Structures ◽  
Metal Metal

Abstract Rational synthesis of sub-nanocatalysts with controllable electronic and atomic structures remains a challenge to break the limits of traditional catalysts for superior performance. Here we report the atomic-level precise synthesis of Pt/graphene sub-nanocatalysts (from single atom, dimer, and to cluster) by atomic layer deposition, achieved by a novel high temperature pulsed ozone strategy to controllably pre-create abundant in-plane epoxy groups on graphene as anchoring sites. The specific in-plane epoxy structure endows the deposited Pt species with outstanding uniformity, controllability and stability. Their size-depended electronic and geometric effects have been observed for ammonia borane hydrolysis, revealing a volcano-type dependence of intrinsic activity on their sizes. Their active site structures have been identified based on extensive characterizations, dynamic compensation effect, kinetic isotope experiments and density function theory simulation. The Pt dimers show the highest catalytic activity and good durability than Pt single atoms and nanoparticles, ascribed to the unique C-Pt-Pt-O (C5Pt2O, metal-metal bond dimer) active site structure. Our work provides new insights into the precise tailoring and catalytic mechanism in sub-nanometer level.

Fine-Tuning Futures

ASHA Leader ◽  
2017 ◽  
Vol 22 (6) ◽  
Author(s):  
Christi Miller
Keyword(s):  
Fine Tuning

Food Safety Security: A new Concept for Enhancing Food Safety Measures

2012 ◽  
Vol 82 (3) ◽  
pp. 216-222 ◽  
Author(s):  
Venkatesh Iyengar ◽  
Ibrahim Elmadfa
Keyword(s):  
Food Safety ◽  
Hazard Analysis ◽  
Warning System ◽  
Shared Responsibility ◽  
Fine Tuning ◽  
Strategic Action ◽  
Surveillance Network ◽  
Measurement Systems ◽  
Critical Control Points ◽  
The Impact

The food safety security (FSS) concept is perceived as an early warning system for minimizing food safety (FS) breaches, and it functions in conjunction with existing FS measures. Essentially, the function of FS and FSS measures can be visualized in two parts: (i) the FS preventive measures as actions taken at the stem level, and (ii) the FSS interventions as actions taken at the root level, to enhance the impact of the implemented safety steps. In practice, along with FS, FSS also draws its support from (i) legislative directives and regulatory measures for enforcing verifiable, timely, and effective compliance; (ii) measurement systems in place for sustained quality assurance; and (iii) shared responsibility to ensure cohesion among all the stakeholders namely, policy makers, regulators, food producers, processors and distributors, and consumers. However, the functional framework of FSS differs from that of FS by way of: (i) retooling the vulnerable segments of the preventive features of existing FS measures; (ii) fine-tuning response systems to efficiently preempt the FS breaches; (iii) building a long-term nutrient and toxicant surveillance network based on validated measurement systems functioning in real time; (iv) focusing on crisp, clear, and correct communication that resonates among all the stakeholders; and (v) developing inter-disciplinary human resources to meet ever-increasing FS challenges. Important determinants of FSS include: (i) strengthening international dialogue for refining regulatory reforms and addressing emerging risks; (ii) developing innovative and strategic action points for intervention {in addition to Hazard Analysis and Critical Control Points (HACCP) procedures]; and (iii) introducing additional science-based tools such as metrology-based measurement systems.

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