I work in a Chinese university and recently our department has decided to start a Distinguished Lecture Series in Physics. We want to give the invited speaker some kind of document showing that, basically, he has been a speaker at this series. I'm not sure what's the best way to write this sentence. I'm not even sure what this kind of document should be called. A certificate? Some kind of award? Please give me some clue. Thank you very much.
Firstly, on what to call this document, I would suggest "Bonafide Certificate of Acknowledgement" or simply "Certificate of Acknowledgement" as that's what it is exactly, as opposed to being an award of any kind.
Secondly, on what to write in the document, I would suggest something on the lines of the following:
"This is to certify the participation (or) contribution of ____Mr/Ms. XXXXXX____ as ____Subject Matter Expert / Distinguished Speaker____ in Distinguished Lecture Series in Physics held at ____XXXXXX University____ on DD-MMM-YYYY. [[Optional note of thanks]] [[Authorized Signatory]] "