Antonio Correia on "create shortcode with data get dynamic"

Hi. If someone could help me, I thanks.

I have follow code;

$termo= "[product_page id='".get_product()->the_ID."']";
echo do_shortcode($termo);

the goal is to transform in a string code like this

[product_page id='231']

but what I get is:
231 [product_page id='']

Appreciate any help.
Thanks