Hexagonal CuCo Prussian Blue Analogs for Higher Gas Adsorption

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Solution Overview

Problem

Conventional Prussian blue analogs (PBAs) face challenges due to non-periodic and random defect distribution, rapid microcrystalline formation, brittleness, and low specific surface area, limiting their application in fields like gas storage and separation.

Innovation Solution

A new synthesis strategy is developed to produce hexagonal phase copper-cobalt Prussian blue analogs with controlled crystal structure and increased specific surface area, utilizing a co-precipitation method without high-temperature treatment, resulting in prism-shaped crystals with larger channels and interstitial spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional cubic PBA structure is used, then synthesis is straightforward, but specific surface area is low and gas adsorption capacity is limited

Engineering Contradiction:

Improvesynthesis straightforwardnessVSAvoidspecific surface area

Core Design Contradiction:

Ease of manufactureVSArea of stationary object

Solution Approach 1:

The patent changes the crystal structure parameter from cubic to hexagonal phase, which fundamentally alters the material's morphology and surface characteristics. This phase transition enables the formation of prism-shaped crystals with significantly increased specific surface area (exceeding 1000 m²/g) while maintaining a simplified one-step synthesis process through controlled co-precipitation at room temperature.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If defect engineering is applied to regulate PBAs, then specific requirements can be achieved, but defect distribution becomes non-periodic and random, making atomic scale study difficult

Engineering Contradiction:

Improvespecific requirement achievementVSAvoiddefect distribution control

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent introduces controlled local defects (vacancies) at specific lattice positions within the hexagonal PBA structure. Rather than random defect distribution, the vacancies are strategically positioned to maintain periodicity and long-range order, enabling both tailored functional properties and clear atomic-scale structural characterization through diffraction methods.

Inventive Principle:

Principle #3Local quality

3Device complexity

If conventional cubic PBA is synthesized, then crystal structure is simple, but channels and interstitial spaces are limited, reducing gas storage capacity

Engineering Contradiction:

Improvecrystal structure simplicityVSAvoidgas storage capacity

Core Design Contradiction:

Device complexityVSQuantity of substance

Solution Approach 1:

The patent transitions from the three-dimensional cubic lattice to a hexagonal lattice structure with distinct layered arrangements and channel systems. This dimensional reorganization creates expanded interstitial spaces and accessible pores along the c-axis, significantly increasing the volume available for gas storage while maintaining structural simplicity through the hexagonal space group P6₃/mmc.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Productivity

If rapid microcrystalline formation occurs during synthesis, then synthesis speed is high, but single crystal growth becomes challenging and structural control is lost

Engineering Contradiction:

Improvesynthesis speedVSAvoidsingle crystal growth control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs preliminary structural organization through controlled co-precipitation of metal ions and cyanide ligands in a specific stoichiometric ratio. This preliminary arrangement of building blocks during the precipitation process directs subsequent crystal growth along hexagonal symmetry, enabling both rapid formation and maintenance of long-range crystalline order without requiring slow growth conditions.

Inventive Principle:

Principle #10Preliminary action

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 hexagonal phase PBAs exhibit a specific surface area of at least 1000 m²/g, enhancing gas adsorption capacity by 1.5 times and improving CO₂/CH₄ and C₃H₆/C₂H₄ separation performance compared to cubic PBAs.

Implementation Method 1

utilizing a co-precipitation method without high-temperature treatment

Methodology Applied

Scientific EffectCo-precipitation: Coprecipitation

Implementation Method 2

enhancing gas adsorption capacity by 1.5 times

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS20250388484A1Unconventional phase hexagonal prussian blue analogs with open structures

Publication Date: 2025.12.25 CITY UNIVERSITY OF HONG KONG

AI summary

The present invention relates to a facile synthetic method to synthesize novel hexagonal phase CuCo (H—CuCo) PBAs with high crystallinity, as well as extended synthesis of doping PBAs with hexagonal phase: Fe0.1—CuCo, Fe0.2—CuCo, Co0.1—CuCo, Ni0.1—CuCo, and Zn0.1—CuCo. The hexagonal phase H—CuCo PBAs and the doping sequence of PBAs with hexagonal phase exhibit superior crystallinity and significantly higher intrinsic specific surface area. Meanwhile, H—CuCo PBAs show great potential for gas adsorption and have a positive impact on the development of PBAs for other applications.