NaBH4 raises Ni3+ and speeds NiFe LDH OER
Treating NiFe layered double hydroxide with NaBH4 lifts Ni3+/Ni2+ from 0.39 to 1.32 and gives 95.9% faradaic efficiency for O2.
Source
NaBH<sub>4</sub> induces a high ratio of Ni<sup>3+</sup>/Ni<sup>2+</sup> boosting OER activity of the NiFe LDH electrocatalyst
Study at a glance
- Design
- Other — NaBH4 reduction of NiFe LDH to raise Ni3+/Ni2+ and oxygen vacancies for OER
- N
- Electrocatalysis materials study — no sample N
- Population
- NiFe layered double hydroxide electrocatalysts
- Outcome
- OER activity and O2 faradaic efficiency after hydride treatment
Structured fields used in claim comparison tables when every cited study has a complete layer.
Inspect source passages
NaBH4 raises Ni3+ and speeds NiFe LDH OER
These passages occur verbatim in the stored paper text. They support the points listed below; they do not verify every statement in the explanation.
Ni3+/Ni2+ rose from 0.39 to 1.32 after NaBH4; Fe2+/Fe3+ from 0.40 to 1.49.
Most importantly, the ratio of Fe 2+ /Fe 3+ and Ni 3+ /Ni 2+ increased steeply from 0.40 and 0.39 for NiFe LDH to 1.49 and 1.32 for the NaBH 4 treated sample denoted as NaBH 4 –NiFe LDH (Table S1), respectively.
O2 faradaic efficiency is 95.9%.
Faradaic efficiency = = 4 Fn O 2 /( I × t ) = 95.9%.
What they did
Authors reduced NiFe LDH with NaBH4, quantified Ni/Fe valence by XPS and XAS, mapped oxygen vacancies by EXAFS, and measured OER current and O2 faradaic efficiency.
What they found
Ni3+/Ni2+ rises from 0.39 to 1.32 and Fe2+/Fe3+ from 0.40 to 1.49. Hydride deprotonates Ni–OH and leaves oxygen vacancies near Fe, making Ni3+ and Fe2+ together. O2 FE is 95.9% (7.48×10−5 mol O2 at 50 mA for 10 min). The trick extends to other TM LDHs.
The limits
What it doesn't show
A full electrolyzer lifetime and a complete microkinetic OER mechanism beyond correlating Ni3+ with activity are not provided.
Key terms
- NiFe LDH
- Nickel–iron layered double hydroxide, a leading earth-abundant OER catalyst.
- Ni3+/Ni2+ ratio
- XPS metric that jumps from 0.39 to 1.32 after NaBH4 and tracks OER activity.
- Oxygen vacancy
- Missing lattice oxygen near Fe after hydride deprotonation.
- OER
- Oxygen evolution reaction, the four-electron bottleneck of water splitting.
- Faradaic efficiency
- Here 95.9% of charge becomes O2.
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After NaBH4, Ni3+/Ni2+ is about:
Common questions
What does NaBH4 change?
It enriches Ni3+ (and Fe2+) via vacancies.
How much does Ni3+/Ni2+ rise?
From 0.39 to 1.32.
O2 faradaic efficiency?
95.9%.
Is it only NiFe?
Authors say the strategy generalizes to other TM LDHs.
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