Quasi-Two-Dimensional Metal Nanosheet with Turing Structure Morphology

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Solution Overview

Problem

Highly active nanoscale electrocatalysts suffer from poor intrinsic stability due to thermodynamic unfavorability of sub-nanoscale structures, leading to agglomeration and a sharp decline in catalytic stability, as seen in the mass activity decrease of nano-Pt/C during accelerated stability tests.

Innovation Solution

A quasi-two-dimensional metal nanosheet with a thickness between 4 nm and 12 nm, composed of platinum, nickel, and niobium, featuring a Turing structure morphology with five-fold twins and lattice strain, is synthesized using a method involving sputtering, exfoliation, and ultrasonic treatment to enhance stability and catalytic activity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If nanoscale electrocatalyst structure is used to increase surface-to-volume ratio and catalytic activity, then catalytic activity is improved, but intrinsic stability deteriorates due to thermodynamic unfavorability leading to agglomeration

Engineering Contradiction:

Improvecatalytic activityVSAvoidintrinsic stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The electrocatalyst is segmented into discrete nanocrystals (3-5 nm) arranged in a periodic Turing pattern rather than continuous bulk or random aggregates. This segmentation into ordered units prevents uncontrolled agglomeration while maintaining high surface-to-volume ratio for catalytic activity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention creates a composite structure combining metallic nanocrystals (Pt, Pd, or their alloys) with a periodic Turing pattern morphology. This composite approach integrates the high activity of nanoscale metals with the stability of ordered periodic structures, preventing random agglomeration while maintaining catalytic performance

Inventive Principle:

Principle #40Composite materials

2Productivity

If sub-nanoscale structure is used to maximize active sites, then catalytic activity increases, but structural stability decreases due to thermodynamic drive for reconstruction and agglomeration

Engineering Contradiction:

Improvecatalytic activityVSAvoidstructural stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The Turing pattern structure is pre-formed during synthesis before catalytic operation begins. This preliminary organization of nanocrystals into stable periodic patterns prevents subsequent reconstruction and agglomeration that would otherwise occur due to thermodynamic drive, locking the high-activity sub-nanoscale structure in a stable configuration

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention changes the structural parameters from random nanoscale particles to ordered Turing patterns with specific geometric constraints. This parameter change from disordered to ordered arrangement increases structural stability while maintaining the sub-nanoscale dimensions necessary for high catalytic activity

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The resulting electrocatalyst exhibits improved durability and catalytic stability, with enhanced mass activity and reduced overpotential in hydrogen evolution reactions, maintaining high performance even under prolonged use.

Implementation Method 1

forming a buffer layer by sputtering. A metal layer is formed over the buffer layer by sputtering

Methodology Applied

Scientific EffectSputtering: Sputtering

Implementation Method 2

The buffer layer and the metal layer are exfoliated in an alkaline solution

Methodology Applied

Scientific EffectExfoliation:

Implementation Method 3

An ultrasonic treatment is performed to the buffer layer and the metal layer for at least one cycle

Methodology Applied

Scientific EffectUltrasonic treatment: Ultrasonic Vibration

Implementation Method 4

The quasi-two-dimensional metal nanosheet has a Turing structure morphology including one or more of Turing stripes and Turing spots assembled by individual metal nanocrystals having different orientations via constrained orientation attachment

Methodology Applied

Scientific EffectLattice strain:

Data Source

PatentUS20240018673A1Electrocatalyst having quasi-two-dimensional metal nanosheet having turing structure morphology

Publication Date: 2024.01.18 CITY UNIVERSITY OF HONG KONG

AI summary

The invention discloses an electrocatalyst includes a quasi-two-dimensional metal nanosheet having a thickness ranging between 4 nm and 12 nm. The quasi-two-dimensional metal nanosheet includes platinum (Pt), nickel (Ni), and niobium (Nb). The quasi-two-dimensional metal nanosheet has a Turing structure morphology including one or more of Turing stripes and Turing spots assembled by individual metal nanocrystals having different orientations via constrained orientation attachment.