Control of Electrons Spin Eliminates Hydrogen Peroxide Formation During Water Splitting

Andreas Vargas Jentzsch; Anja R.A. Palmans; Beatrice Adelizzi; Claudio Fontanesi; E.W. Meijer; Francesco Tassinari; Kiran Vankayala; Ron Naaman; Wilbert Mtangi

arxiv: 2606.01648 · v1 · pith:CPHL5UMPnew · submitted 2026-06-01 · ⚛️ physics.chem-ph

Control of Electrons Spin Eliminates Hydrogen Peroxide Formation During Water Splitting

Wilbert Mtangi , Francesco Tassinari , Kiran Vankayala , Andreas Vargas Jentzsch , Beatrice Adelizzi , Anja R.A. Palmans , Claudio Fontanesi , E.W. Meijer

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Ron Naaman

This is my paper

Pith reviewed 2026-06-28 12:37 UTC · model grok-4.3

classification ⚛️ physics.chem-ph

keywords spin selectivitywater splittingchiral semiconductorshydrogen peroxidephotoelectrochemical cellsZn-porphyrinstriarylamineselectron transfer

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The pith

Coating anodes with chiral dyes suppresses hydrogen peroxide formation in water splitting via spin selectivity.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper demonstrates that coating the anode with chiral organic semiconductors from helically aggregated Zn-porphyrins and triarylamines imposes spin selectivity on electron transfer. This dramatically reduces hydrogen peroxide as a competing side product while increasing overall cell current tied to water splitting. Evidence comes from comparing chiral and achiral versions with magnetic conducting AFM measurements. A sympathetic reader would care because peroxide formation limits electrode stability and efficiency in photoelectrochemical hydrogen production. The approach addresses overpotential and oxidative damage through control of electron spin.

Core claim

Coating the anode with chiral organic semiconductors from helically-aggregated dyes as sensitizers imposes spin-selectivity; hydrogen peroxide formation is dramatically suppressed while the overall current through the cell, correlating with the water splitting process, is enhanced.

What carries the argument

Chiral organic semiconductors from helically-aggregated Zn-porphyrins and triarylamines that enforce spin selectivity during electron transfer at the anode.

If this is right

Photoelectrode oxidative stability improves because the peroxide side reaction is reduced.
Water splitting efficiency rises as more current contributes to hydrogen production rather than peroxide.
Spin selectivity extends to other multiple-electron-transfer reactions in electrochemical cells.
Chiral dye-sensitized photoelectrochemical cells become viable with better performance.
The underlying mechanism of spin selectivity in electron transfer gains experimental support from the AFM data.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

The same helical-dye approach could be tested on cathodes or in non-photoelectrochemical electrolyzers.
If spin selectivity proves general, it might reduce unwanted side products in other oxidation reactions.
Device integration would require checking long-term stability of the organic coating under operating conditions.
Alternative chiral sensitizers beyond porphyrins and triarylamines could be screened for stronger effects.

Load-bearing premise

The observed drop in hydrogen peroxide and rise in current result specifically from spin selectivity induced by the chiral coating rather than other chemical or structural effects of the materials.

What would settle it

An achiral coating with equivalent chemical structure but no helical aggregation produces the same peroxide suppression and current increase, or magnetic AFM shows no difference in spin polarization between chiral and achiral dyes.

read the original abstract

The production of hydrogen through water splitting in a photoelectrochemical cell suffers from an overpotential that limits the efficiencies. In addition, hydrogen-peroxide formation is identified as a competing process affecting the oxidative stability of photoelectrodes. We impose spin-selectivity by coating the anode with chiral organic semiconductors from helically-aggregated dyes as sensitizers; Zn-porphyrins and triarylamines. Hydrogen peroxide formation is dramatically suppressed, while the overall current through the cell, correlating with the water splitting process, is enhanced. Evidence for a strong spin-selection in the chiral semiconductors is presented by magnetic conducting (mc-)AFM measurements, where chiral and achiral Zn-porphyrins are compared. These findings contribute to our understanding of the underlying mechanism of spin selectivity in multiple electron-transfer reactions and pave the way towards better chiral dye-sensitized photoelectrochemical cells.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Desk Editor's Note private letter to a colleague

The spin-selectivity story for H2O2 suppression is undercut by missing achiral controls on the actual cell data.

read the letter

The paper's main move is coating the anode with helically aggregated chiral Zn-porphyrins and triarylamines to filter electron spin, which they say cuts H2O2 formation and raises photocurrent in a photoelectrochemical cell. The mc-AFM section does compare chiral and achiral Zn-porphyrins to show spin selectivity, and that part looks like a clean control.

The electrochemical results, however, are reported only for the chiral coatings. The abstract gives no parallel runs with achiral versions on the same cell metrics, so the link between spin filtering and the observed changes stays open to other explanations like altered surface chemistry or light harvesting.

That gap is the main soft spot. The mc-AFM evidence is useful on its own for people tracking chiral-induced spin selectivity, but the water-splitting claim needs the missing controls to hold up. The work is experimental and straightforward, with no circular math or invented parameters.

This is worth a look for labs already doing spin-selective electrochemistry or dye-sensitized cells. A reader gets a concrete example of the approach and the mc-AFM data, but would want the full controls before treating the mechanism as settled.

I would send it to peer review if the authors can supply the achiral cell data or explain why they are absent; the topic is relevant enough that referees should see it.

Referee Report

1 major / 2 minor

Summary. The manuscript claims that coating the anode with chiral organic semiconductors (helically-aggregated Zn-porphyrins and triarylamines) imposes spin-selectivity in a photoelectrochemical water-splitting cell. This leads to dramatic suppression of hydrogen peroxide formation as a competing process and enhancement of the overall photocurrent. mc-AFM measurements comparing chiral and achiral Zn-porphyrins are presented as evidence for strong spin selection in the chiral materials.

Significance. If the central attribution to spin selectivity holds after appropriate controls, the work would demonstrate a practical application of chiral-induced spin selectivity (CISS) to multi-electron transfer reactions, offering a route to reduce overpotentials and improve oxidative stability in photoelectrochemical cells without additional catalysts. This could inform design of chiral dye-sensitized systems and advance mechanistic understanding of spin effects in water oxidation.

major comments (1)

[Electrochemical measurements / Results] Electrochemical performance data (H2O2 suppression and photocurrent enhancement): these are reported only for the chiral coatings. No parallel cell measurements with achiral analogs are described, in contrast to the mc-AFM section which explicitly compares chiral and achiral Zn-porphyrins. This is load-bearing for the central claim, as the improvements could arise from differences in surface chemistry, light harvesting, or catalytic sites rather than spin filtering.

minor comments (2)

[Abstract] Abstract provides no quantitative values, error analysis, or statistical details on the magnitude of H2O2 suppression or current enhancement, limiting assessment of effect size and reproducibility.
[Methods] Methods details for the photoelectrochemical cell setup, H2O2 quantification, and any controls are not summarized, which is required to evaluate the experimental design.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their careful reading of the manuscript and for identifying this important gap in the presented evidence. We address the major comment below and will revise the manuscript accordingly.

read point-by-point responses

Referee: [Electrochemical measurements / Results] Electrochemical performance data (H2O2 suppression and photocurrent enhancement): these are reported only for the chiral coatings. No parallel cell measurements with achiral analogs are described, in contrast to the mc-AFM section which explicitly compares chiral and achiral Zn-porphyrins. This is load-bearing for the central claim, as the improvements could arise from differences in surface chemistry, light harvesting, or catalytic sites rather than spin filtering.

Authors: We agree that the absence of achiral controls for the photoelectrochemical cell performance data represents a limitation in the current manuscript. While the mc-AFM measurements explicitly compare chiral and achiral Zn-porphyrins to demonstrate spin selectivity, the H2O2 suppression and photocurrent results are shown only for the chiral systems. This leaves open the possibility that the observed effects could stem from other differences in the coatings. In the revised version we will add parallel electrochemical measurements using the corresponding achiral Zn-porphyrin and triarylamine coatings under identical conditions. These data will be presented alongside the existing chiral results to isolate the contribution of spin selectivity. revision: yes

Circularity Check

0 steps flagged

No circularity: purely experimental claims with no derivation chain

full rationale

This is an experimental paper reporting photoelectrochemical measurements and mc-AFM data on chiral vs. achiral coatings. No equations, parameters, or mathematical derivations are present in the abstract or described results, so none of the enumerated circularity patterns (self-definitional, fitted-input-as-prediction, self-citation load-bearing, etc.) can apply. The central claims rest on direct comparison of observed currents and H2O2 levels rather than any reduction of outputs to inputs by construction.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

The claim rests entirely on experimental observations of current and peroxide levels with chiral versus implied achiral controls; no free parameters, axioms, or new entities are introduced.

pith-pipeline@v0.9.1-grok · 5716 in / 892 out tokens · 25206 ms · 2026-06-28T12:37:42.912468+00:00 · methodology

discussion (0)

Reference graph

Works this paper leans on

2 extracted references

[1]

Palmans2, Claudio Fontanesi3, E.W

1 Control of Electrons’ Spin Eliminates Hydrogen Peroxide Formation During Water Splitting Wilbert Mtangi1, Francesco Tassinari1, Kiran Vankayala1, Andreas Vargas Jentzsch2, Beatrice Adelizzi2, Anja R.A. Palmans2, Claudio Fontanesi3, E.W. Meijer*2, and Ron Naaman*1 1Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel; 2Ins...

2007
[2]

David, M. A. Iron, D. Milstein, Science. 234, 74 – 77 (2009). 12 K. Sivula, F. Le Formal, M.Grätzel, ChemSusChem. 4, 432 – 449 (2011). 13 J. Brillet, et al., J. Mater. Res. 25, 17-24 (2010). 14 M. T. Mayer, C. Du, D. Wang, J. Am. Chem. Soc., 134, 12406−12409 (2012). 15 P. E. M. Siegbahn, R. H. Crabtree, J. Am. Chem. Soc. 121, 117-127 (1999). 16 J. P. McEv...

2009

[1] [1]

Palmans2, Claudio Fontanesi3, E.W

1 Control of Electrons’ Spin Eliminates Hydrogen Peroxide Formation During Water Splitting Wilbert Mtangi1, Francesco Tassinari1, Kiran Vankayala1, Andreas Vargas Jentzsch2, Beatrice Adelizzi2, Anja R.A. Palmans2, Claudio Fontanesi3, E.W. Meijer*2, and Ron Naaman*1 1Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel; 2Ins...

2007

[2] [2]

David, M. A. Iron, D. Milstein, Science. 234, 74 – 77 (2009). 12 K. Sivula, F. Le Formal, M.Grätzel, ChemSusChem. 4, 432 – 449 (2011). 13 J. Brillet, et al., J. Mater. Res. 25, 17-24 (2010). 14 M. T. Mayer, C. Du, D. Wang, J. Am. Chem. Soc., 134, 12406−12409 (2012). 15 P. E. M. Siegbahn, R. H. Crabtree, J. Am. Chem. Soc. 121, 117-127 (1999). 16 J. P. McEv...

2009