Sulfidic Pentlandite Electrocatalyst for Hydrogen Evolution
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Solution Overview
Problem
Current compositions for electrocatalytic water splitting do not meet the requirements of high current density, resistance against sulfur compounds, and stability of catalytic activity, particularly in start-stop operations.
Innovation Solution
A composition of Fe9-a-b-cNi1-aCobMcS8-dSed, where M is an element with an effective ionic radius of 70-92 pm, and specific ranges for a, b, c, and d, with ≥90 wt.% in the pentlandite phase, is used for the hydrogen evolution reaction, incorporating Co to reduce overpotential and allowing up to 50% Se substitution without losing structural integrity or activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If platinum is used as electrocatalyst for hydrogen evolution reaction, then high catalytic activity is achieved, but high cost and sensitivity to sulfur compounds occur
Solution Approach 1:
The patent replaces expensive platinum with a cost-effective sulfidic composition containing Fe, Ni, Co, and optional M elements. This substitution maintains catalytic functionality while eliminating the high cost and sulfur sensitivity associated with platinum, making the electrocatalyst both economically viable and resistant to sulfur poisoning.
Solution Approach 2:
The patent employs a composite sulfidic composition with multiple metal elements (Fe, Ni, Co, and optional M) in specific ratios. This composite structure synergistically combines the properties of individual metals to achieve high catalytic activity, stability, and sulfur resistance that single-metal catalysts cannot provide alone.
2Adaptability or versatility
If metal sulfides are used as electrocatalysts, then platinum-free alternative is provided, but insufficient stability and start-stop properties are observed
Solution Approach 1:
The patent optimizes the stoichiometric ratios of metal elements (Fe: 0.3-0.7, Ni: 0.2-0.6, Co: 0.1-0.4, M: 0-0.2) and controls synthesis parameters to achieve a specific pentlandite phase structure. This precise parameter control transforms unstable metal sulfides into a stable, reusable electrocatalyst with excellent start-stop properties.
Solution Approach 2:
The patent introduces M elements (Cu, Mn, Cr, Nb) with specific ionic radii (70-92 pm) to locally modify the catalyst structure. This local modification enhances the overall stability and start-stop performance of the electrocatalyst while maintaining its platinum-free composite nature.
3Productivity
If conventional electrocatalysts are used, then hydrogen production is achieved, but high overpotential and low current density result
Solution Approach 1:
The patent achieves low overpotential (≤300 mV at -10 mA/cm²) by precisely controlling the metal composition ratios and synthesizing a specific pentlandite phase structure. This optimized structure facilitates efficient electron transfer and hydrogen evolution, dramatically improving productivity while reducing energy consumption compared to conventional electrocatalysts.
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 composition achieves higher current densities than platinum-based materials, maintains activity during hydrogen production, exhibits superior start-stop behavior, and is stable against sulfur poisoning, enhancing the efficiency and sustainability of hydrogen production.
Implementation Method 1
The composition is used for electrocatalytic splitting of water, preferably for hydrogen evolution reaction
Implementation Method 2
electrocatalytic water splitting
Data Source
AI summary
The present invention relates to the use of a composition of formula (I): Fe9-a-b-cNiaCobMcS8-dSed, wherein M stands for one or more elements having in the ionic state an effective ionic radius in the range of 70-92 pm, a is a number within the range of 2.5≤a≤3.5, more preferably 2.7≤a≤3.3, b is a number within the range of 1.5≤b≤5.0, more preferably 1.5≤b≤4.0, most preferably 2.5≤b≤3.5, c is a number within the range of 0.0≤c≤2.0, more preferably 0.0≤c≤1.0, d is a number within the range of 0.0≤d≤4.0, more preferably 0.0≤d≤1.0, wherein the sum of a, b and c is in the range of 5≤a+b+c≤8 and wherein ≥90 wt. % of the composition is in the pentlandite phase for electrocatalytic splitting of water, preferably for hydrogen evolution reaction.