透射原位气氛反应样品杆

Hummingbird Scientific has recently launched the atmospheric pressure gas TEM holder that enables in-situ high resolution imaging in atmospheric pressure gasses. The microfabricated gas cells that are designed and fabricated by Hummingbird Scientific also allow the application and measurement of signals to specimens inside the gas cell.To assure this system can be safely used on a daily basis, the holder has a quick sealing design and comes with a turbo pump checking station specially designed for TEM environmental holders.

Overview

Our In-situ TEM Gas Cell Specimen Holder provides a complete solution for studying material behavior in gases and at elevated temperatures. Gases are introduced via one of our optional, dedicated gas delivery systems to the micro-fabricated environmental cell inside. The pressures inside the cell that can be controlled over ranges from high vacuum to above atmospheric pressure. Local specimen heating is provided via an integrated thin film heater, with a temperature sensor carefully calibrated to ensure accurate temperature readings. To ensure clean delivery of gasses the entire holder is designed to be bakeable at 160°C. The instrumentation enables researchers to gain atomic resolution images of gas-solid interactions at real-world reaction temperatures and pressures. With this holder, the mechanisms behind important industrial reactions, like catalysis, now can be studied in operando.

Gas Delivery

Single-Channel gas delivery system

Hummingbird’s single-channel atmospheric gas delivery system was designed to deliver one pressure controlled experimental gas depending your experimental needs.

Multi-Channel gas delivery system

The Hummingbird multi-channel gas delivery system is a configurable and scalable solution for gas delivery to the Hummingbird Scientific gas holder.

Heating

The thin film heating system for the gas holder is designed to discretely heat the sample within the gas cell to temperatures up to 500oC or up to 800oC, depending on the needs of the experiment.

Heating is controlled from a custom designed heating control box which features closed loop temperature control through the software interface with a calibrated sensor on the chip.

Application Examples

Gas Catalysis

Fuel cell research

Growth of nano-structures

Atomic layer deposition

Atomic scale image of a TiN thin film at 500°C in 1.1 atmosphere nitrogen in the Hummingbird Scientific in-situ TEM gas holder, imaged using a 300 kV FEI corrected Titan in BF mode. The FFT (inset) shows information below the 2 ? level.

Images courtesy of Dr. Huolin Xin and Dr. Haimei Zheng (Lawrence Berkeley National Laboratory).

Kirkendahl effect in Co nanoparticles

Researchers at the Lawrence Berkeley National Laboratory and Hummingbird Scientific have directly imaged the process of Co nanoparticle oxidation and reformation as Co is heated to 250°C and 350°C respectively. This study shows the specific morphological changes that occur during these processes, shedding light on the underlying mechanism that governs this process.

Right: Formation of hollow core oxide shells when Co nanoparticles are heated from 150°C to 250°C in 1 bar of flowing oxygen.

Far Right: Coalescence of the oxide shells as particles are further heated from 250°C to 350°C.

Reference: In Situ TEM Study of Catalytic Nanoparticle Reactions in Atmospheric Pressure Gas Environment. H.L. Xin, K. Niu, D.H. Alsem and H. Zheng, Microsc. Microanal. (2013) 19 1558.

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