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# Taiwan team uses CO-tolerant PtTe₂ for a bias-free seawater artificial leaf
- URL: https://research-pop.com/taiwan-team-uses-co-tolerant-ptte2-for-a-bias-free-seawater-artificial-leaf/
- Published: 2026-09-28T14:38:24.000Z
- Updated: 2026-09-28T14:38:24.000Z
- Author: ResearchPOP

![](https://storage.ghost.io/c/7c/5e/7c5e0911-739b-4a35-94eb-3e810bf78ba7/content/images/2026/09/Screenshot-2026-09-28-at-16.15.15.png)

Source: [https://advanced.onlinelibrary.wiley.com/doi/10.1002/aenm.71637](https://advanced.onlinelibrary.wiley.com/doi/10.1002/aenm.71637?ref=research-pop.com)

## At a glance

A collaboration across National Taiwan University, National Taiwan Normal University and Academia Sinica reports a pH-gradient artificial-leaf system that couples photoelectrochemical hydrogen evolution with electrochemical ethylene-glycol oxidation. CO-tolerant 1T-PtTe₂ serves as the anodic catalyst and is also incorporated into the silicon-based photocathode.

Under one-sun illumination and without an external bias, the integrated device reached 37.85 mA cm⁻² in fresh water and 37.18 mA cm⁻² in natural seawater. During a 120 h test, it continuously generated hydrogen and glycolate. The paper connects the electronic structure of PtTe₂ with its resistance to CO-derived poisoning, then places that chemistry within a pH-gradient device.

## Background

An artificial leaf uses light-absorbing materials and catalysts to convert solar energy into chemical products. In a conventional photoelectrochemical water-splitting system, hydrogen evolution occurs at the cathode and oxygen evolution at the anode. The oxygen-evolution reaction is kinetically demanding and requires a relatively high potential, so it can consume a substantial part of the voltage supplied by the light absorber.

Natural seawater adds further complications. Chloride can participate in competing anodic reactions, while Mg²⁺ and Ca²⁺ can form deposits near an alkaline cathode and obstruct its surface. The composition and pH of each compartment must be managed alongside light absorption and catalysis.

One strategy is to replace oxygen evolution with the oxidation of an organic molecule that reacts at a lower potential and forms a useful product. Here, ethylene glycol is converted mainly into glycolate. Ethylene glycol is also a product of alkaline polyethylene-terephthalate hydrolysis, linking the reaction concept with a possible feed derived from waste PET.

Platinum can catalyse ethylene-glycol oxidation, but strongly adsorbed CO-like intermediates can occupy its surface sites and suppress the reaction. Bonding Pt with another element can shift its electronic states and alter the balance between activating ethylene glycol and holding poisoning intermediates too strongly. The researchers examine whether Pt–Te hybridisation provides that balance in a bias-free seawater device.

## Research question

Can Pt–Te p–d hybridisation weaken the adsorption of CO-derived intermediates while preserving ethylene-glycol activation, and can the catalyst be combined with a silicon photocathode and a pH gradient to operate in natural seawater without an external bias?

## Inside the study

![](https://storage.ghost.io/c/7c/5e/7c5e0911-739b-4a35-94eb-3e810bf78ba7/content/images/2026/09/image-37.png)

The team prepared single-crystalline 1T-PtTe₂ by a tellurium-flux method. Diffraction, Raman spectroscopy and microscopy supported its layered structure, while X-ray photoelectron and absorption measurements established Pt–Te coordination and an electronic environment distinct from metallic Pt and platinum oxide.

The authors connect hybridisation between Pt 5d and Te 5p states with charge redistribution and a downward shift of the Pt d-band centre. In their interpretation, this reduces back-donation into the antibonding orbitals of CO-derived adsorbates and weakens their surface interaction. Ethylene glycol must still bind and react, while poisoning intermediates should be removed more readily.

In 1 M NaOH containing 1 M ethylene glycol, PtTe₂ required 0.42 V versus RHE to reach 10 mA cm⁻², compared with 0.66 V for Pt. At higher potential, the respective currents were 195.4 and 58.2 mA cm⁻². PtTe₂ also showed a smaller Tafel slope, 52.3 versus 121.1 mV dec⁻¹, and lower charge-transfer resistance, 19.18 versus 43.98 Ω cm².

Product measurements showed that glycolate Faradaic efficiency peaked at 96.4% at 0.9 V versus RHE. During a 24 h three-electrode test at this potential, PtTe₂ retained 58.72% of its initial anodic current, whereas Pt retained 6.41%. Nuclear magnetic resonance spectroscopy identified glycolate as the dominant liquid product, with only a trace signal from formate.

CO-stripping peaks occurred at lower potential on PtTe₂, indicating easier oxidative removal of adsorbed CO. In situ Raman spectroscopy detected a CO-derived band at 2,080–2,100 cm⁻¹ on Pt but no discernible corresponding feature on PtTe₂ over the same range. Together with the forward-to-backward current ratio, these results support lower accumulation of CO-derived species. They do not directly identify every intermediate.

Calculations gave an ethylene-glycol adsorption energy of −0.45 eV on PtTe₂. The proposed pathway begins with hydroxyl dehydrogenation at 1.25 eV, followed by carbon dehydrogenation at 1.07 eV and hydroxylation at 1.8 eV before glycolate forms. Calculations and ultraviolet photoelectron spectroscopy both placed the Pt d states below those of Pt(111), supporting the electronic-structure explanation for CO tolerance.

The catalyst was then tested in alkaline natural seawater. Ethylene-glycol oxidation reached about 188.5 mA cm⁻² at 0.97 V, and the anodic current retained about 94% after 120 h, close to the 95% retention measured in fresh water. After 500 C of charge had passed, the system produced 1,228 μmol glycolate and 83.6 μmol formate, corresponding to Faradaic efficiencies of 94.5% and 4%. The glycolate production rate was 1.54 mmol h⁻¹ cm⁻². Ethylene glycol obtained from PET hydrolysis showed similar polarization and long-term behaviour under the tested conditions.

For the hydrogen-producing side, the researchers incorporated PtTe₂ into a PtTe₂/graphene/Si heterojunction photocathode operated in acidic electrolyte. At 0 V versus RHE, it produced −37.05 mA cm⁻² in fresh water and −36.4 mA cm⁻² in natural seawater. Over six hours, hydrogen-production rates were 690 and 680 μmol h⁻¹ cm⁻², respectively, with Faradaic efficiencies above 98%.

The complete artificial leaf separates the acidic hydrogen-evolution compartment, at pH 0, from the alkaline ethylene-glycol-oxidation compartment, at pH 13.7, using a bipolar membrane. The difference in proton activity creates a thermodynamic potential shift of about 0.8 V. This helps match the electrode potentials to the photovoltage of the illuminated silicon photocathode, allowing operation without an external bias.

Under one-sun illumination, the integrated device delivered 37.85 mA cm⁻² in fresh water and 37.18 mA cm⁻² in natural seawater at zero external bias, without iR compensation. After 120 h, it retained nearly all of its initial photocurrent. Average hydrogen-production rates were 663 μmol h⁻¹ cm⁻² in fresh water and 604 μmol h⁻¹ cm⁻² in seawater, while glycolate rates were 332 and 297 μmol h⁻¹ cm⁻². The accumulated hydrogen-to-glycolate ratio stayed close to two, consistent with the coupled reaction stoichiometry reported by the authors.

## Takeaways and outlook

The paper joins catalyst design with reaction and device engineering. Pt–Te p–d hybridisation shifts the electronic structure of Pt and is associated with lower accumulation of CO-derived intermediates during ethylene-glycol oxidation. Replacing oxygen evolution lowers the anodic potential requirement and makes glycolate as a second product, including when PET-derived ethylene glycol is used under the reported conditions.

At the device level, an acidic photocathode, alkaline anode, bipolar membrane and pH gradient are designed as one system. Their potential alignment allows the illuminated device to sustain paired hydrogen and glycolate production in natural seawater without an externally applied bias for 120 h.

The results belong to the stated laboratory configuration, electrolyte compositions and illumination conditions. Further development would need to examine larger areas, product separation, fluctuating sunlight and the inputs needed to maintain the pH gradient. The central advance here is the integration of a CO-tolerant anodic reaction with a pH-gradient photoelectrochemical architecture.

## About the researchers

Yung-Hung Huang (National Taiwan University and Academia Sinica) is the first author. Chun-Wei Chen (National Taiwan University and Academia Sinica) and Di-Yan Wang (National Taiwan Normal University and Academia Sinica) are the corresponding authors.

The other authors are Tsung-Hsin Liu and Chih-Ying Huang (National Taiwan University and Academia Sinica), Ya-Wen Tang, Tzu-Chin Huang and Fang Yu Shen (National Taiwan Normal University), Meng-Chi Hsieh and Chun-Chih Chang (Chinese Culture University), Shao-Ku Huang and Po-Hsien Wu (National Taiwan University), Ya-Lun Ho (National Institute for Materials Science), and Raman Sankar (Academia Sinica).

## Original research

Yung-Hung Huang; Tsung-Hsin Liu; Ya-Wen Tang; Meng-Chi Hsieh; Tzu-Chin Huang; Chih-Ying Huang; Shao-Ku Huang; Po-Hsien Wu; Fang Yu Shen; Ya-Lun Ho; Chun-Chih Chang; Raman Sankar; Chun-Wei Chen; Di-Yan Wang. CO-Tolerant Ethylene Glycol Oxidation on p–d Hybridized Platinum Ditelluride for Seawater Artificial Leaves. *Advanced Energy Materials* (2026). [https://doi.org/10.1002/aenm.71637](https://doi.org/10.1002/aenm.71637?ref=research-pop.com).

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## Research POP Notes

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