Standard Platinum Counter Electrode

Description

이 표준 백금 카운터 전극은 내화학성 에폭시 막대 끝에 실장된 코일형 백금 와이어(순도 99.99%)가 특징입니다. 프릿 유리관은 상대 전극을 주 시험 용액에서 분리합니다. 유리 튜브에는 표준 전기화학 셀의 14/20 포트에 튜브를 장착하는 데 적합한 PTFE 어댑터가 장착되어 있습니다. 프릿 유리관은 제거하여 전기화학 셀에 직접 장착할 수도 있습니다. 코일은 대략 4.7cm2의 표면적을 갖는 0.5mm OD Pt 와이어로 제작됩니다. 코일의 대략적인 직경은 9mm입니다. 6.9mm OD 검정색 에폭시 로드의 길이는 150mm입니다. 로드와 코일의 전체 길이는 약 180mm입니다.

Documention

 Q&A. 백금 또는 그라파이트 상대 전극 선택 요령은?

Let’s first review the purpose of the counter electrode. The counter electrode completes the circuit for the potentiostat and drives current through the electrochemical cell. As such, the counter electrode has to have a large area than the working electrode and be sufficiently active at passing current through the electrochemical cell, while still being “inert” to not affect the electrochemistry at the working electrode.

With that said, the platinum counter electrode has a smaller area than the graphite rod and is more expensive. However, the platinum counter electrode is more “active” than the graphite rod, meaning that it intrinsically passes current more easily than the graphite rod electrode. Some researchers might need to add a “sacrificial agent” to the counter electrode if there is nothing for the counter electrode to oxidize or reduce. Platinum is so good at oxidizing and reducing that a sacrificial agent is rarely needed, but it might be needed for a graphite rod (depends on the system). Because it requires more voltage to drive a current through the graphite rod, the user would benefit from using a potentiostat with a large compliance voltage. Compliance voltage is rarely an issue, but it can be an issue with some customer setups

The last consideration is platinum or carbon contamination. If the customer is doing CO2 reduction research, using a graphite rod could be problematic because the graphite could leech out of counter electrode and produce false positives. However, the same argument could be made for platinum, and that platinum from the counter electrode is getting on the working electrode and contaminating your system.