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EnviroESCA

Home Surface Physics Laboratory – Hydrogen Technology Center Facilities EnviroESCA

Advanced Capabilities for Surface Analysis and Operando Studies

The EnviroESCA system at Charles University's Department of Surface and Plasma Science offers state-of-the-art near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) capabilities. Designed for both dry and liquid environments, this advanced instrument provides detailed insights into the chemical and electronic states of materials under real operating conditions.

EnviroESCA is accessible through the CERIC-ERIC organization, both in their regular semester calls for proposals and for shorter Fast Track commissioning studies.

Features and Applications of EnviroESCA

Near-Ambient Pressure XPS: Perform analyses at pressures up to 50 mbar, enabling studies of complex samples, such as catalysts, thin films, and biological materials, in their natural or working states.
Operando Measurements: Dedicated cells allow operando studies in electrocatalysis and thermocatalysis (detailed descriptions below).
Diverse Material Compatibility: Measures a wide range of materials, including metals, semiconductors, and polymers. Charge effects are mitigated using gaseous atmospheres for compensation.
Monochromated Al Kα X-ray Source: Ensures high-quality spectra.
Laser-Based Spot Selection: Enables precise targeting of the 300 µm analysis spot for homogeneity assessments or measurements of small/inhomogeneous samples.
Depth Profiling via Ar Sputtering: Facilitates analysis of material composition at various depths.
Enhanced Surface Sensitivity: Higher pressure measurements increase surface sensitivity, revealing additional surface characteristics for the price of longer measurements.

Open access

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Operando Cells for Advanced Studies

Operando Heating Cell

Functionality: Enables material analysis at elevated temperatures up to the equivalent of 600 °C in 10 mbar of N₂.
Sample Size: Accommodates samples up to 10 mm in diameter.
Gas Compatibility: Measurements in other gases (O₂, CO, CO₂, etc.) are possible, though maximum temperatures vary depending on gas properties adn reactivity. Please contact us for details.

Operando Water Electrolyzer (WE) Cell

This titanium-based cell supports direct operando measurements of both the anode and cathode in water electrolyzers.
Working Principle: The reaction is fed with water permeating through a polymer membrane, maintaining sufficient reactant levels while allowing accurate XPS measurements.
Precise electrochemistry: Integrated with a BioLogic SP-50e potentiostat for precise monitoring of oxidative and reductive catalyst changes during various electrochemical procedures. The potentiostat is also capable of electrochemical impedance spectroscopy (EIS) measurements.
Material Suitability: Best suited for electrically conductive working electrode catalysts.
Further details: Detailed operational principles are described in this publication, demonstrated with a magnetron-sputtered Ir catalyst for the PEM-WE anode.

Operando Half-Cell for Acids

A PEEK-based cell with a 3-electrode setup for operando electrochemical studies in acidic environments.
Working Principle: Similar to the WE cell, but water is replaced with the desired acid (e.g., H₂SO₄, HClO₄), enabling studies of materials with lower electrical conductivity.
Electrodes: Includes an Ag/AgCl reference electrode and a Pt wire counter electrode. Other electrodes can be considered upon request.

Operando Half-Cell for Bases

A PEEK-based cell with a 3-electrode setup for operando electrochemical studies in basic environments.
Working Principle: Operates like the acidic half-cell, replacing water with the desired base (e.g., KOH) to expand material compatibility.
Electrodes: Features an H₂ reference electrode and a Pt wire counter electrode. Other electrodes can be considered upon request.

Detailed technical specification

Electron Spectrometer

Hemispherical Electron Analyzer with 150 mm mean radius
Differentially pumped lens system
One-dimensional delayline detector with up to 400 channels

X-ray Source

Al Kα micro-focused monochromator
Rowland circle diameter of 600 mm
Spot sizes of 200 μm - 1 mm, optimized to analysis area

Charge Neutralization System

Intrinsic charge compensation by photoionization
Effectiveness can be tuned by introducing inert gas through the gas dosing system

Pumping System

Pressure range from 10^-7mbar to 50 mbar in standard configuration
Turbomolecular pumps
Oil-free backing pumps
Chemical resistive pumping system

Gas Dosing System

Fully automated and software controlled
Two gas dosers at analysis position
Mass flow controllers

Cameras

3 digital microscopes for sample navigation and documentation

Sample Environment RT-NAP

High precision 3-axis sample stage
Sample sizes of up to 120 mm in diameter and 40 mm in height, 50 mm diameter addressable
Compatible to EnviroESCA standard sample holders
Gas dosing system for process or purge gases
Downstream RF plasma cleaner
Digital microscope for sample observation
Spare ports 1 x DN40CF, 2 x DN16CF

Ion Source for Sputter Depth Profiling in UHV

SPECS ion source
5 keV extractor type source producing scannable and focussed ion beam
Differential pumping system

Sample Environment RT-NAP

Allows for variable temperature applications together with the Button Heated Sample Holder (BHSH) or the Peltier Cooled Sample Holder (PCSH)
PID controller for temperature control and stabilization
Water cooling for sample receiving stage
Modification of sample receiving stage for accepting BHSH and PCSH

Heated Sample Holder (BHSH)